I get quotation from various ID companies and discovered their quote are at least 100% mark-up vs contractor.
For instance, powder coated casement window & grilles quote was $5.5K from ID whilst I got the same thing at $2.5K by going direct to grilles specialist.
Now almost done with my renovation. At $40k I revamped the entire house, changed whole house flooring, plastering, rewiring, false ceiling, new casement windows, painting, curtains, lightings, bathroom accessories, stove & hob, new water pipes, EVERYTHING in !
I used my previous wet work contractor (he did my 1st house, good price & quality). I also managed to find a carpenter who is a sub-con for ID companies. He quoted me market price, though his price is still a few $K higher than conventional carpenter. At least I still get ID grade carpentry since I by past the middle man (ID) and went direct.
My guess is, to get exactly the same thing as what I have now, I will probably have to pay at least $80K to ID company
But bear in mind, lots of coordination work. Because I ended up as the project manager, need to manage time line between different parties.