Yes for example we have (depending on loan) min. 6-9 months required. so even if they sell it prior they still pay interest for that period.

a flip requires CASH for closing costs and points, a down payment, holding costs, costs to cover any overage you weren't able to borrow...so, the issue with flipping is that (1) it takes capital, and (2) the return is 6-12 months out.

This property required a new roof and some basic renovations.

Without any experience, mistakes and learning in this industry can be very expensive.

Some lenders will offer you 100% financing but it will be expensive money to borrow. 

Unfortunately, it's more expensive today than it has been in the past, but guess what, it will be more expensive in the future the longer you wait.

We require one months rent as deposit so that gives us 30 days to get someone else in there.

@Clayton Silva is right vacancies and turn costs are generally our biggest expenses.

Prefab and modular projects often require a different draw schedule than stick built homes.

Same principle applies to the seller's expenses and insurance--they're pointless for your underwriting.