How far in terms of help have you gone for a friend?

I have gone far, maybe a bit too far. Recently my husband and I let friends live with us for over 9 months, rent and utility free. It was a huge sacrifice for our family, one I do not regret. It did not end well, but we did learn a lot from the experience. We now know not to leave such an offer open-ended. Next time, there will be a set time limit and discussion of what is a deal breaker and what isn't will be had beforehand. I can look back on it now and know that these friends did not set out to be destructive and did not have the intention of mooching. But it spiraled to that with no accountability and no boundaries. Once we tried to set those boundaries, things went haywire and we lost what we thought were some great friends.