Why bring a contractor before making an offer on the property

[Ererz Choen]

Why bring a contractor before making an offer on the property, if I'm going to do an Inspection?

If I add an Inspection Contingency to the contract, why not make an offer based on a general analysis of the property and only after winning and after receiving the inspector's report, get accurate quote for the renovation from the contractor?

If it OK - I take it and if not, I have the option to get out of the contract.