I'd really appreciate some advice please!

I've had a couple of quotes to do a tiling job in my bathroom.

One guy in particular seemed the most professional but there were a couple
of things he said which concerned me, one of which was a technical issue.

I assumed he'd tile one day, and then return the next day (or later) to do
the grouting, once the tile adhesive had time to dry out.

However, he said he'd be able to do both tiling and grouting in one day, and
that it wouldn't make a noticable difference to the job. I'm a bit
suspicious, but admit that I'm not aware of tiling techniques, so he could
maybe be using a fast-set adhesive which dries quick enough to allow
grouting quickly?

Can anyone confirm this - is it possible, or more accurately, recommended,
to grout and tile the same day?

(On a slightly different note, he claims he's one of the guys the big sheds
subcontract to do their tiling, and he did come recommended from a local
tile warehouse)

Thanks in advance

Eno