Fix'n Flips - When to pull permits?

[Shane Thompson]

I'm trying to wrap my head around this process. I've found some points (quick Google) that show the requirements for permits, however I'm unclear as to WHEN.

Before any demolition? after? Any requirements after contract work has been completed?

Having the permit "in hand" for the contractor performing the work seems the right way?

I don't want to waste any time between holding and construction costs. Anyone with experience on WHEN is best?