This might be controversial but I take ages and get paid for it. At least 4 days for me but then I am not a full time tiler and do whole room refurbs from start to finish. I used to use a tiler and he wasn't bad but not up to the
standard I expect hence why I'm doing it again. I don't use rapids as I'm not fast enough so laying and grouting on same day is not possible however I know some tilers will grout "when the tiles stop moving enough" rather than waiting the recommended times.
To put this into perspective, a window reveal that needs a bit of squaring up (they all do right?) with properly mitred trims and consistent gaps all round will take me most of a morning. Just getting the trims right will take me about an hour.
So the question is really, like others have said, if you get paid for how long it takes you, then fine. Others that are "fast" might be getting paid for longer and are knocking it out fast to make more per day than day rate.
Also one man's good job is another man's adequate and without close inspection, it's hard to know where the speed/quality line is. Personally I can't see how a job good enough for me could be done in 2 days and I don't mean that to be insulting; it's just more about me not being able to do it regardless in that time.