The device stays put while you roll a ball, so the hand and arm stop traveling across the desk.
also: trackball mouse, rollerball mouse
The basics
What to know about keyboards & mice
The only parts you touch all day
Your keyboard and mouse are the only computer parts your skin touches all day. A keyboard is a grid of switches under molded caps, read by a controller that reports which keys are held down. A mouse is a downward facing camera photographing your desk thousands of times a second, wrapped around two buttons and a scroll wheel. Both are sold on large numbers now, and most of those numbers describe engineering headroom rather than anything a hand can detect.
Three key mechanisms
Three key mechanisms cover nearly everything on sale. A rubber dome collapses one molded silicone sheet onto printed circuit film below. This gives a soft landing at the end of the stroke and 5 to 10 million presses of rated life per key. A scissor switch shortens that dome to 1.2 to 2 mm of travel and steadies the cap with an X shaped hinge, which is the flat laptop feel. Mechanical switches give each key its own sprung housing, roughly 4 mm of travel, a trigger point near 2 mm and 50 to 100 million presses. They arrive in three feels: linear glides evenly at about 45 grams of force, tactile places a bump at the trigger point and asks 55 to 65 grams, and clicky adds a noisemaker that carries down a phone line. Magnetic switches, labeled Hall effect after the sensor that tracks a moving magnet, let you set the trigger anywhere from 0.2 to 3.5 mm.
How a mouse sensor works
The sensor in a mouse is a small camera lit by an LED, comparing frames 6,000 to 12,000 times a second to work out how far the body moved. DPI, meaning dots per inch and sometimes written CPI, counts the steps reported for each inch of travel: raise it and the pointer covers more screen for the same hand movement, while nothing gets more precise. Between 800 and 1600 suits most people, and past roughly 3200 the sensor amplifies hand tremor along with intention. A 26,000 DPI headline states what the chip can be configured to do, not a setting anyone uses. Connection changes far more. A cable reports every millisecond at the usual 1,000 Hz polling rate. That means position updates sent per second, and a 2.4 GHz radio with its own receiver lands within about a millisecond of that. Bluetooth speaks in scheduled slots every 7.5 to 15 milliseconds, so quick movement arrives slightly late, and it repays you with months of battery and pairing to three machines.
Choose by how you sit
Choose by how you sit and what you do. Mechanical Keyboards suit anyone typing for hours who wants to pick the feel, since the switch is the product. Membrane Keyboards belong on shared desks, reception counters and in the spares drawer. Low-Profile Keyboards keep one muscle memory between a laptop and a desk. Split Ergonomic Keyboards earn their retraining if your wrists angle outward or your shoulders round forward to reach the keys. Wireless Mice fit almost any desk, Vertical Mice untwist a forearm that aches below the elbow, and Trackballs stop the arm traveling. This is what a crowded desk or a standing workstation needs. Pain in one wrist or thumb makes the pointing device the first thing to change, because a mouse loads one small group of muscles for hours while typing spreads the work across ten fingers.
What a mechanical board weighs
Each gain sends a bill elsewhere. A mechanical board weighs 900 g to 1.4 kg, costs several times a dome board and can get you asked to type more quietly. Cutting the cable hands you a battery to manage: an office mouse on AA cells runs 12 to 24 months, a rechargeable one polling at 1,000 Hz gives 40 to 70 hours of movement, and pushing to 8,000 Hz cuts that to roughly a quarter for a difference under a millisecond. Splitting a keyboard costs two to four weeks of typing speed and leaves you clumsy on ordinary boards for longer. Standing the hand upright cures forearm rotation and makes fine cursor work harder. A trackball frees your desk and asks one thumb or two fingers to do all the pointing.
Type a full paragraph
Judge with your hands rather than a datasheet. Type a full paragraph with capitals and punctuation, then listen to the space bar, shift and enter keys, because rattling stabilizers under the long keys are the commonest flaw and the hardest to fix afterward. Keycaps molded in PBT, a dense plastic, resist the greasy shine that softer ABS caps develop within 6 to 12 months, and letters molded into the cap outlast printed ones, which wear off the home row first. Hot-swap sockets accept switches by pressing them in, turning a wrong feel into a 20 minute correction rather than a soldering job. On a mouse, check your fingertips do not curl past the front edge, then confirm settings save inside the device so it behaves the same on a computer you cannot install software on.
The upkeep everyone skips
Upkeep here is brief and usually skipped. Twice a year, pull the keycaps with a wire puller, turn the board over and brush out what falls, since debris under a switch causes the repeating key people blame on software. Wipe the mouse sensor window with a dry cotton swab as soon as the pointer stutters. A spill ends a membrane board almost at once and gives a mechanical one a fair chance if you unplug it, lay it face down and wait 48 hours. Install firmware updates for the keyboard, the mouse and the receiver, which fix wireless dropouts and wake delays that no setting on the computer reaches. A mouse registering two clicks from one press has a worn switch, not a driver fault.
Buyer checklist
Before you buy keyboards & mice
Electronics combine hardware, software and services. Compatibility and support life matter as much as the headline specification.
01
Map the whole setup
Confirm the ports, operating system, network, accessories, apps and services the product must work with.
02
Check the support period
Look for a clear security and software-update policy, especially on connected products and discounted older models.
03
Separate included from subscription
Find out which recording, storage, analytics, content or remote features need an ongoing payment.
04
Plan for repair and data
Check battery and spare-part service, warranty handling, account controls and how personal data can be exported or deleted.
Measure the clear desk width beside your monitor before choosing a layout. A full-size board runs about 440 mm, a tenkeyless one, which means a board with the number pad removed, about 360 mm, and a 65 percent board, which also drops the function row, about 305 mm. Add 250 mm to the right for the mouse to move.
Your hand length decides mouse size, so measure from the wrist crease to the tip of the middle finger. Under 170 mm counts as small, 170 to 190 mm as medium and above 190 mm as large. A palm grip wants a mouse within about 20 mm of that length; claw and fingertip grips take one size down.
Set the keyboard at or just below elbow height with your upper arms hanging straight down. Fold the flip-out feet away instead of using them, because raising the back edge bends the wrists upward. Bending past roughly 15 degrees raises pressure inside the wrist. If your knuckles sit higher than your wrists, the board or the desk is too tall.
Leave 100 to 150 mm of bare desk in front of the keyboard so your forearms have somewhere to land. A board pushed to the front edge makes you hold your arms up for the whole day, and no wrist rest corrects that.
For a split keyboard, measure between the two bony points at the front of your shoulders, usually 360 to 460 mm on an adult, and set the halves that far apart. Check the connecting cable reaches, since some ship with enough for only 300 mm of separation.
Count your free USB ports. A dedicated receiver takes one port per device unless the pair shares a single receiver. A keyboard with a pass-through socket needs a data-capable port rather than a charging-only one. A 2.4 GHz receiver placed beside a high speed port or an external drive stutters, so keep a 150 mm extension cable to move it clear.
Care
Caring for keyboards & mice
Twice a year, unplug the board, pull the keycaps with a wire puller and tip it upside down over a bin. Debris wedged under a switch is the usual cause of a key that repeats itself or stops registering. It gets blamed on software almost every time.
Clean the mouse sensor window with a dry cotton swab the moment the pointer starts stuttering, then look at the smooth pads on the base. Those pads wear through in 12 to 24 months and are sold as replacements. A worn one lets the shell drag on the desk.
Lift the ball out of a trackball every two to four weeks and wipe the three bearings and the sensor window. Skin oil builds into a ridge on each bearing, and that ridge is what makes the pointer skip rather than glide.
Pull the cable the second liquid reaches a keyboard, turn it face down and wait 48 hours before testing it. Sugary drinks need the affected switches rinsed with plain water first. A membrane board rarely survives either way, because the liquid sits trapped between the printed films.
Alkaline cells come out of any mouse or keyboard going unused for more than a month, since a leaking cell corrodes the contacts past repair. Store a rechargeable device near half charge rather than flat, because a cell left empty for months may never take a full charge again.
Install firmware updates for the keyboard, the mouse and the receiver, then check your key remapping survived. Firmware fixes wireless dropouts, wake delays and double-click faults that no computer setting can reach, and major updates often wipe stored profiles.
Questions
Common questions
Which switch should I choose if I type all day?
Start with a tactile switch at 55 to 65 grams. The bump tells your finger the key registered. You stop pressing sooner and hit the base plate less often, which is where finger fatigue comes from. Linear switches suit you if you bottom out anyway and prefer a smooth stroke. Keep clicky switches out of any shared room, because the click carries down a phone line clearly.
Does a higher DPI make me more accurate?
No. DPI sets how far the pointer travels per inch of hand movement, not how finely the sensor sees. Most people work between 800 and 1600, and above about 3200 the sensor reproduces hand tremor along with your intention. Leave the operating system pointer speed at its middle setting as well, since higher settings skip pixels instead of adding detail.
Is wireless slower than wired?
That depends which wireless. A 2.4 GHz link with its own receiver lands within about one millisecond of a cable, below what anyone perceives. Bluetooth updates in slots every 7.5 to 15 milliseconds, and that shows in fast games and precise drag work. For typing, email and spreadsheets, neither difference is noticeable in practice.
Do I need a number pad?
Only if you enter figures for more than about ten minutes a day. Removing it narrows the board by roughly 80 mm and brings your mouse hand that much closer to your body, which shortens every reach your shoulder makes over eight hours. For occasional numbers, a separate pad placed on the left costs little and moves out of the way when you are done.
How long should a keyboard and mouse last?
A mechanical keyboard runs 10 to 15 years, with keycap shine and a frayed cable arriving well before any switch fails. A membrane board gives three to five years of heavy use before the domes soften unevenly. Mouse buttons are the weak point everywhere. Switches are rated 20 to 50 million clicks, roughly two to five years, and one press registering twice means that switch is worn.
Will a split ergonomic keyboard fix my wrist pain?
It addresses two causes, not all of them. Separating the halves removes the outward wrist bend needed to reach a narrow board, and tenting reduces forearm rotation. Neither helps if the real problem is desk height, a mouse parked far to the side, or hours without a break. Pain, numbness or tingling that persists needs a clinician rather than another purchase.
Are 8,000 Hz polling rates worth paying for?
Rarely. A 1,000 Hz mouse reports every millisecond, and 8,000 Hz cuts that to 0.125 milliseconds, a change smaller than one thousandth of a second. It also drains a wireless battery around four times faster and adds measurable load to the computer. Spend the difference on a shell that fits your hand, which affects every hour you use it.
Should I use a wrist rest?
Use one between bursts of typing, not during them. Resting the wrist while your fingers work presses the soft underside into the pad and anchors the hand, so your fingers stretch for keys instead of the hand moving to them. Match the rest height to the front edge of the keyboard, usually 10 to 25 mm, because a rest taller than the board tilts your hands upward.
