They had 3 modes of work.
1) Work diligently - No concerns when they were in this mode, they moved quickly, both working effectively. This is how movers should be. But it was only ~30% of the time, notably for the 1st half of the move.
2) Somewhat working - Sometimes 1 guy would work, the other guy just watched. Sometimes it was moving an item, sometimes it was wrapping an item with plastic wrap - but there was only 1 guy working, the other guy would either just watch or he'd just walk off somewhere else for a while (but not moving anything). ~50% of the time.
3) Not working - Sometimes they'd both just disappear from the house, they'd be hanging out in the truck, outside taking a call, or just simply chatting with each other. This happened frequently, notably in the last half of the move. I can't count the number of times I had to go looking for them and ask them what's up/what's the delay/etc. ~20% of the time.
I'd say they stretched what could have been a 3 hour job (max 4 hrs) based on their "diligent" working mode into a 6 hour job based on their mixed working mode of dilgent/somewhat working/not working.