For most riders, the classic three-pocket layout is all you need. It's been the cycling standard for decades because it simply works—two side pockets and one center pocket give you enough room for a spare tube, tire levers, a multi-tool, some snacks, and your phone on a typical road, gravel, or mountain bike ride.
The three-pocket design also distributes weight evenly across your lower back, which helps prevent the jersey from sagging or shifting as you ride. Each pocket is easy to reach behind you without looking, so you can grab food or your phone while staying focused on the road ahead.
Where three pockets might not cut it: if you want a secure, zippered spot for valuables like keys or a wallet, or if you're bikepacking and need to carry extra layers and supplies. In those cases, look for a jersey with a fourth zippered pocket or even five-plus pockets. But for everyday riding, three is the sweet spot.