Cotton is still the most common material for a Jiu-Jitsu belt, and cotton belts earn that popularity by holding a knot under grappling pressure better than most synthetic blends, which tend to loosen or slip once they've broken in. The trade-off is maintenance: cotton fades and frays faster than polyester-blend belts, and it needs more careful washing to avoid shrinking. A synthetic or poly-cotton blend resists color loss and holds its shape through heavier wash cycles, which suits someone who trains five or six days a week and doesn't want a belt care routine layered on top of everything else. Choose cotton if you want the traditional feel and a knot that holds under pressure; choose a synthetic blend if wash-and-forget matters more to you than how the belt feels in hand. Cotton isn't a great fit for someone who trains daily and can't commit to washing on cold and hanging it to dry, since that's where cotton belts start to shrink and lose shape fastest. Neither material is the "correct" choice, and the honest answer depends on how often you're willing to hand-wash a belt.
A belt that's too short to wrap around the waist twice with even tails is the single most common ordering mistake new grapplers make. Retailers usually size belts off height and weight charts, but the real variable is how you knot it: a double wrap and a square knot eat up close to twice the length of a single loop tied loosely, and most people end up with tails somewhere around 20 to 30 centimeters once it's tied right. Someone at 175 cm who ties a tight double wrap needs a longer belt than someone the same height who prefers a looser single pass. Choose a size up if you know you'll tie a full double wrap with long tails, because a belt that runs slightly long is easy to adjust while one that comes up short can't be fixed without buying again.
Belt color tracks rank, and in adult Jiu-Jitsu that generally runs white, blue, purple, brown, then black. If you're not sure which one applies to you, your coach is the only reliable source, since promotion pace and internal grading standards vary by academy and aren't standardized the way some retail pages imply. A store has no way to verify rank at checkout, so responsibility for ordering the correct color sits with the buyer, not the seller.
Kids belts aren't just smaller versions of an adult belt. Youth Jiu-Jitsu programs usually run a longer color ladder between white and the equivalent of an adult rank, with narrower, shorter belts built for a child's frame rather than a scaled-down adult cut. If you're buying for a young grappler, check the academy's own youth grading chart before ordering, since belt requirements for kids programs vary more between schools than adult requirements do.
A belt that's starting to fray at the tip or fade at the knot isn't a sign it needs replacing early. In most Jiu-Jitsu gyms, a worn, faded belt reads as time on the mat rather than neglect, which is part of why plain cotton stays popular even though it shows wear faster than synthetic options. What actually shortens a belt's useful life is leaving it damp and balled up inside a gym bag after class, since mildew and odor set in there faster than ordinary wear ever would. A belt hung up to dry the same day it gets soaked through holds up noticeably longer than one left sitting wet between sessions, and that habit matters more than any gi belt sizing chart ever will.
Belt rank only applies to gi training. No-gi doesn't use a belt at all, so a BJJ belt is really only needed for the gi sessions on your schedule, competition check-in, or grading days rather than daily wear on the mat. Someone who trains mostly no-gi with only the occasional gi class can usually get by with one belt for years, since it sees a fraction of the wear a daily gi student puts on theirs.
Belt stripes get added over months or years, so a well-built belt is meant to last through an entire rank rather than getting swapped out every few months. One that's splitting at the seams or losing its knot grip well before the next stripe is worth replacing early, but chasing a fresh-looking belt for appearance alone usually isn't worth the cost. Most grapplers replace a belt only when the material actually gives out, not on a schedule, and a belt bought once at the right size tends to outlast several stripes before it needs a second look.
