Rules you bend for your friends stop being rules. They turn into favors.

The moment a rule depends on who is asking, it stops being a rule, and everybody understands the new arrangement straight away. You have not been generous, you have made yourself the gatekeeper, which turns every future request into a referendum on friendship. The people who are not your friends noticed too.

Decide what the rule is when nobody is asking for an exception, and say it the same way to everyone. If you want to be flexible, change the rule out loud, for all of them. Consistency is less fun and much easier to live with.