On commercial work I was part of a two man team and in 12hrs we'd tile and grout 80-100m2 per day but that was when I was younger and it was non stop all day. The work certainly wasn't shabby, the floors were usually big flat open areas (shop floors) and everything was to hand. Basically the system was that one person would spend the day labouring, ensuring tiles were handy, adhesive was mixed and ready, cuts were done as required and areas were swept as we worked across the site and the other guy would literally spend the day on his knees. At the end of the day, everything we had tiled was grouted and washed off twice using washboys so that that area could be handed over to the other trades. The following day we would swap over roles. I spent many months with blisters on the back of my knees from the straps of the kneepads.
These days I work at a nicer pace, and I work alone the majority of the time. For an average bathroom I allow myself about four days but this includes Silicon to all the movement joints etc and any thing extra that the customer requires