When I first started, I once did 7 weddings in 9 days and at the end of that period, I had almost nothing left in me. I honestly didn't think any of the 7 shoots suffered but it almost took the life out of me! I am really driven and the thought of getting 7 opportunities to shoot was the only thing that mattered (besides the financial reward). As in any industry that you are in, hard work is really important but in the creative industry, you really need to watch that you don't burn yourself out.
The 110 weddings that I did included half day shoots and ROMs. So it wasn't as bad as doing an AD once every 3 days but it was still a crazy period. Also, we tried to meet all our couples on the same day. That way, it left me with some free days to at least go catch a movie with the wife.