Some inspectors require primer to be used on PVC. I know an EC that has carried around a can of clear primer for years and never used it. When the inspector asks why there is no visible primer on his pipe runs, the EC says it's because it's clear and shows him the can.
I have toyed with PVC for years and I really do think that the primer makes for a better connection, but do we really need the glue (cement) to do anything more than keep the pipe from falling apart? It's not our job to make the pipe waterproof.
I think that, although much stronger, purple primer looks like crap on a pipe run. I know how to do it so the primer is barely visible, but most electricians slap it on like BBQ sauce on a side of roasting venison.
Do we really need to use primer?
I think it's overkill for our application, but I still use it.
Do you inspector types gig people for not using primer? What code requires it?