How cheap can parquet be?

And one more question for the professionals: does gluing (by a specialist) take significantly longer than the clip system? What would you roughly estimate the time required for 50 sqm? Or does gluing make sense if the parquet is rather low budget?

Depends on whether the room is crooked. The actual installation should not take much more than 1 day. But why? It is actually done per sqm and not by hours.

No, there's nothing particularly intricate about it.

This is how it was with us:
Day 1 sand the room and pour leveling compound
Day 2 lay parquet (about 20 sqm)
Day 3 oil everything

But he was only there for a few hours each time.
For installing 50 sqm continuously, it should go quickly.

We want to use [Fertigparkett] if anything. So it wouldn't need to be oiled anymore, I don't know about [Ausgleichsmasse]... There is such a [Trittschalldämmung], which would probably have to be removed if glued down. But estimated 20-25 hours of professional work for just under 50 sqm - is that roughly realistic or will we be way over that?

I would see that as an absolute maximum. For us, it was maybe 12 hours in total.