adding a MIL apartment. If I could finish it for around 50k, and rent it out for at least $800 (before utilities), I'm having a hard time thinking of many downsides. I would build a separate entrance (my basement in the back is only underground by about 3 feet. I would have a great room with a kitchen, a bathroom, a small area for laundry, and a very large bedroom. All in all about 600 square feet for the apartment. I would pay extra to really "soundproof" the walls and ceiling so I don't hear the renters.

I would get another large family room finished I can use as part of the deal. I'm on a 15 yr mortgage that I've been paying on for 4.5 years. I would reset back to the 15 years and drop my interest rate by another .25 to .5%. I would pay 11 months of the rent directly towards my mortgage keeping the other for a rainy day fund (lack of renter, having to fix something, etc.). The "break-even" point, where my mortgage would be the same as if I didn't do it is just under 5 years away. The deal would be I would need to rent out for at least that long. At that point, I got my basement finished for free, have an apartment I can rent out to kids or aging parents, increased the value of my home, and a potential future income source.

So CB .. tell me the downsides because I'm having a hard time finding them!