Limits are good. Limits mean that you can test your software under both min and max conditions.

If there’s no hard limit, then the limit exists merely in the developer’s mind as what they consider sensible or not.

Inevitably there will be some user who takes your software past what the developer considered sensible. And unknowingly and silently, this user becomes a tester in production.

The real problem is not DRYing your limits. There should always be one central point of truth, one constant that determines what the limit is.