Let's get straight to it — here's what actually matters on this one.

• With arms hanging naturally, the sleeve hem should end right at your wrist bone — not covering your hand, not riding up your forearm.
• For blazers, aim to show about half an inch of shirt cuff below the jacket sleeve — this is the classic 'quarter inch to half inch' rule.
• Sleeves that are too long bunch at the wrist, trapping sweat in the exact spot most exposed to friction from watches, desks, and steering wheels.
• Sleeves that are too short expose more forearm to sun and abrasion, and often mean the shoulder seam doesn't fit either.

The fit-and-fabric-health takeaway: Correct sleeve length keeps fabric from bunching against the wrist and forearm — one of the most sweat-prone, friction-prone areas on the body.

Next up: check out our guide on how collar size actually works.