Agree, keep pressing contractor is not a good thing. end up they give you shit output.
But in another hand, some contractor just markup way too high for everything.

For example:-
They put 3 indonesian that been paid RM100 x 60 days = RM 18000.
Some basic material that less than RM20k
And own supervisory once awhile....

and they can charge RM 180,000

if get them to buy the material, they might even markup more.

Why I said so:-
Just coincident i got a group of friend buy semi d at semenyih.

Mr A, Extend kitchen and the above floor, move toilet location, knock few walls, and cabling and etc....with all material...
He outsource all at once at RM450k.

Mr B, do the same by buying own material, just outsource to the same vendor
Better material at RM80k, workmanship RM250k

Mr C, do all same, find another contractor.
Better quality, same material = RM81k (duno why extra 1k)
workmanship, RM80k

Mr D, do all same, find one designer + worker.
material even much much better = RM100k, designer(pm) = RM25k , worker = RM27000 (he paid RM150 per day)
on top of that he buy rice and drinks for the worker also.

end up mr D output is the best and cheapest