Couples break up all the time, and you'll want to be protected if your condo ends up in the middle of that.

. - if you need an attorney to break up, you're married.

but they must break up when he turns 18 right?

although i can say of 3 plus decades of owning some form of investment or rental property i have never had a tenant sue me for anything other than a deposit squabble.litigation in real estate tends to be in partnership break ups or other things when you buy and sell.. but if your worried about slip fall or someone getting killed or maimed on your property and suing you then insurance is by far the best protection.  

Do you have any insights about the additional cost break up and any critical learnings you got from taking up that project?

You see it on larger M&A "break up fee"

And I advise you to have them do it anyway, because if you break up with your girlfriend, do you really want to be the sole signatory on the note?

Yes sometimes partners team up and take over the world but its too often the case that partners break up and, just like divorces, two people who were perfectly compatible in the beginning are ready to rip each others throats out toward the end. 

But you now need to add her to the lease...and if the child is 18 years or older, then they need to be added to the lease too.But if they break up or whatever, you get to deal with this nuisance all over again because I'm sure the lady will say she's not paying rent since she moved out.

Break up with the folks who you're not interested in using so that they know you're not in the mix anymore.