Can UID be reused

Hi

I have two questions

  1. I am just curious. Is reusing UID is linux allowed or should it be avoided and why?

  2. Can one create a user in Linux without a password and if so, what will the account be rendered as, disabled or inactive ?

Regards

For question 2, I guess it would depend on the distro, but a password isn’t mandatory (it can be set to null). The account will still be active

Does question 1 mean a vacated UID, or do you mean can more than one account have the same UID ?