Setting aside money for your piti, and also vacancy, property management, maintenance, and capital expenditures is a great formula for success.

I'm assuming with a lender like PenFed who doesn't need to do an appraisal if the CLTV is below a certain value, that they're using some formula to ballpark the current value.

IF she said make an offer then here is my formula for calculating those thing:ARV ( $275k) x .07 minus the rehab = Price SO I would offer maximum $142500. 

It's fun throwing around numbers and percents and formulas but this is how you actually figure out your costs when you have a specific deal your underwriting.

This might not be an appropriate path for you, but, whatever the path you choose, remember that a slow and steady progress along your pre-determined path will take you a long way: hard work, integrity, and results...that is my simple formula.

The formula you mentioned, is that for buying and holding the property?

There are many formulas for success. 

It is up to you to choose your profit margin - not a formula.

I'm not interested in Windsor, but am really curious about formulas to run student rentals, and how people work leasing agreements, bylaws, etc. 

As it stands now, I will continue to sing the same song, same verse every time the occasion arises.