It varies from band to band with me. I'm always grateful for help packing up and carrying gear in the band where the singer and I share PA duties. And yes I know that any 'help' I receive means untangling and tidying at a later date, but I actually find a good tidy and sort through quite cathartic.
In my other two main bands I'm just the bassist and carry minimal gear so I am often first to finish. I will help carry for the others but I have a major bugbear:
People who refuse to park or move their vehicles as close to the exit door of the venue as is humanly possible. Oh and reverse up to the door too, you moron.