Initial rehab estimate

[Konstantin Podyachev]

Hello guys. The newbie question here!

I’m currently looking to buy my first fix and flip property and had a question about initial estimate repairs cost. 
I’ve heard it’s the best to have the same scope of work passed over to several contractors and compare their estimates apples to apples. But how you get that initial estimate to price the deal right at the first place?
Calling an inspector for every walkthrough could be quite expensive, and calling contractors for every walkthrough could be quite exhausting for them. 
Or Maybe I’m looking at the logistics at the wrong angle? Please feel free to share your workflow when you don’t have a trusted contractor yet, and a lot of experience. I would appreciate the help.