increase the rent?

[Andy Young]

Hi!
I am buying a $140,000 3 bedroom two bath duplex. All comparable rents in this area on craigslist (and the zestimate for rent) are 750-900 dollars. There is a woman in one of the units that is only paying 625. My question is, when her lease expires, should I increase her rent?

If so, I am sure I could get a renter who pays $800, should I increase it to that? Or should I go halfway? I have heard that there is value in a renter that stays put, pays on time, and takes care of the place. Should I leave it alone?

Some related facts:

She had been paying 600 for the last 7 years and last year (I assume because they wanted to sell the place) and the rent was just increased to $625.

The apartment is in good shape but may need new carpet or floor.

We will make three thousand after the mortgage payments without increasing the rent.

Thanks for you opinion!