It all depends on how stuck you get. In my jeeping days, we've had two 9,000# winches with snatch blocks pulling a 4,000# jeep and not able to get it to move. We had to do some digging and still put a 3rd 9,000# winch straight line to the vehicle to finally get it out. It was buried to the doors in a sticky glue clay.
Then there was the situation where I nose dived my jeep into a hole and couldn't back up. Used a 1,500# ratchet to give me the little extra I needed to get out. It was a slow process of putting as much strain on the ratchet, then back up the jeep about an inch, repeat process about 60 times to get unstuck.
Usually they recommend 1-1/2 times the vehicle weight and this takes into account using a snatch block at times.