A cycling shoe should feel snug enough that your foot doesn't shift inside it under hard pedalling, but not so tight that you feel numbness, tingling, or a pulse point within the first ten minutes. The right tension holds the foot still without cutting off circulation — those are two different things, and most fit complaints come from confusing one for the other.
The most common mistake is over-tightening the forefoot to compensate for a loose heel. If your heel lifts when you pedal, cranking down the front of the shoe won't fix it and will instead squeeze the metatarsals, a common cause of hot foot and numb toes on longer rides. The fix is a shoe with a heel cup shaped to hold you without relying on front-of-foot tension, which is why UDOG designs the heel geometry on Distanza and Cento to lock in place at a moderate, comfortable closure tension rather than a maximal one.
How tight is "right" also changes with the closure type. With laces, tension is harder to fine-tune once you're moving, so most riders set them slightly looser than feels perfect at a standstill, knowing the foot will settle in after a few minutes of riding. With a dial closure like Twist Tech, you can adjust in small clicks while riding, so the better approach is to start a notch looser than feels secure and tighten gradually as the ride warms up and the foot settles — rather than maxing out the dial before you've even clipped in.
Tension should also change through the ride, not just once at the start. Feet swell in heat and after a couple of hours regardless of fitness level, so a closure that felt right at the start of a four-hour gravel ride will often feel tight by hour three. This is where a two-zone closure, like the dual dials on Cento or the Tension Wrap System on Distanza, earns its keep: you can loosen the forefoot slightly without loosening the heel lock that's keeping your foot stable.
A simple test for correct tension: after tightening, wiggle your toes. You should be able to move them slightly without the shoe moving with them. If you can't feel your toes at all, or if a specific point on top of the foot throbs after five minutes, that's too tight — loosen it before you ride, not after the discomfort sets in, since re-tightening mid-ride rarely fully resolves numbness that's already started.