Kid's Jeans & Jeggings (Bottoms)

One label covers two different garments. Jeans are woven denim with a real fly, a button at the waist and five pockets. Jeggings replace all of that with a knit or heavily stretched fabric that reads as denim, a pull-on elastic waist and, very often, front pockets that are only stitched on.

Denim is a twill weave, which is why diagonal lines show on the face and why the fabric resists tearing. Children's denim usually runs 8 to 12 ounces per square yard, with 1 to 2 percent elastane added so a child can squat without the knee going stiff. Inside the waistband of most pairs sits a strip of elastic with buttonholes punched along it, reachable through a slot. Moving that button takes about two inches out of the waist without touching the length. Since children often outgrow length a year before width, that one detail is what keeps a pair in service.

Joggers give up the fly and the structure for an elastic ankle and a soft hand. So they win at the playground and lose at a family dinner. Leggings are all stretch, with no pockets and no waistband hardware. Jeggings sit between the two, borrowing the look of denim and the behavior of leggings, which suits a child who wants the appearance without the button.

Older kids at school, cooler months and anywhere knees take a beating are what denim is for, since twill scuffs where jersey tears. Potty training is the clear time to skip it, because a button and fly cost seconds nobody has. Very warm climates are the second, as heavy denim holds heat against the leg.

Slide two fingers into the waistband slot and work the elastic. It should move in clear notches, and the buttonhole strip should feel like woven tape rather than thin flat elastic. Knees lined with a second layer of fabric roughly double the life of a pair on a child who kneels to play. Cold water and an inside-out wash hold the indigo, and a hot dryer is the enemy, since denim loses length before it loses width.