If they can’t provide that, it’s a sign they may not be organized enough to finish the project effectively.

That is nuanced, but a few key elements are not taking the current financials, including rents at face value, another would be adding interior space without creating a bad floor plan, which is often converting a sunroom to a bedroom, finishing a walk-up attic, or finishing an unfinished basement.  

If you like I can send you a proposal for finishing up your build to see where I’m at to see if it still makes sense

To stack wins, lock your numbers and your team before demo: define your buy box and profit target, get two exit plans on every deal (sell or wholetail/rent if days-on-market stretch), line up funding and a backup lender, and get three bids with a needs vs. wants scope tied to ROI, not finishes.

However I had a friend that took 6 months from start to finish.

Just finished a 3/2 around 1400sf for right around $10K.

Even after replacing dimensional lumber with engineered joists due to the wider spans required in the larger homes and using higher end finishes, the numbers are still significantly better. 

It might feel formal, but it protects both sides and keeps the focus on getting the deal across the finish line.

Time, Quality, Budget, and Procedures are not being met/followed/honored and then in a blink of an eye you'll be 9 months in, and your project is at the 2 month mark and your budget is nearly drained and now you gotta find a way to finish this in three months with money out of your pocket or else you will need an extension on your loan which will be 1% of the loan amount and then you'll be carrying a high interest bridge note for 12 months, maybe more. 

I just finished up a BRRRR myself.