Chicago wholesaler - question for contractors and flippers

[Jordan Lanum]

Good afternoon BP!

I am getting into wholesale in the Chicago land area, so far I have had little trouble getting in contact with "motivated sellers" and getting things under contract. I am working on getting my first deal closed now.

Now to my question, I want to get to being a "Pro" at estimating Rehab costs. I have noticed on a few places (including BP) that give a formula of ($30 per sqft multiplied by the sqft of the property) however they mention that number per sqft is different for each area. So I want to ask flippers and contractors

So my questions are as follows

1. Is that a decently reliable formula?

2. What dollar amount per sqft would you recommend I use ( or range)

3. Is there a better way to estimate rehab cost?