I have never hired packers, because to me packing is a very personal process. For one thing, I would never know where anything was when trying to unpack. For another thing, I often go through things as I pack them. I give some away, throw some away, sell some at garage sales and so on. Second of all, hiring packers is very expensive.
I DO hire movers. They come and pack the truck and drive it to the new location, then unpack it. If the move is not too far (I move often), then I also move some of the stuff myself. I never try to move furniture or heavy boxes on my own.