They may miss out on future gains if the neighborhood continues to increase in value.

Renting to a friend can complicate things, especially if you're starting below market rent.

This influx is limiting rent growth nationwide, particularly in the Sun Belt, where oversupply has led to rent declines.Nationwide, vacancy rates edged down to 7.8% as move-ins outpaced move-outs.

I used all the rent and any extra money towards paying them down.

.: Is it legal, per the IRS, to rent my primary home back to myself? 

Did you get any updates on rent control?

Miami Rental Market Update: Rents Drop $200 as Affordability Remains a ChallengeMiami has officially ranked as the second-most unaffordable city in the U.S., but there’s some good news for renters: local rents have dropped to a 3-year low, with decreases of up to $200.

Just 1-2 years without a rent increase will result in 15% behind market.

Ignore the $1,250 per month because that's your cost of housing, if you didn't pay that on the home you'd have paid that in rent so that's a non factor. 

If they support a rent increase, you could look into raising your rents by that amount to offset the cost.