What level of rehab work requires permits?

[Jordan Becker]

Hi folks, what level of rehab work requires that you pull permits, or at least makes it strongly advisable to do so?   I am thinking that some work may be too minor to bother with the permit process, especially since in some locations the process can take a long time.  So how do you decide whether to pull permits for a rehab job (or insist that your contractor do so)?  Thanks.