you got to think about this question.
how far do you want to go to become a handy women.
I do not recomment every investors to take houses that need extensive work.
By intensive work I mean things like:
replace whole roof;
completely redo kitchen
" " bathrooms
Any single item over 5k and total more than 15k.
Flat roof is trouble. You are most likely in need to rip part of the plywood off to replace rotten part. And sooner or later it will leak again...