How to create permission bound forms

Question

I create a lot of web applications that deal with different groups of users creating and editing data.

Usually there are requirements regarding users and what actions they can or cannot perform on the data depending on who they are and what state the data is in.

Should I create a single form for all users to use and build permission bound logic into it?

or

Should I create multiple forms for use by different groupd of users?

or

Should I do something else?

Thanks,