You can only give someone the benefit of the doubt so many times.

If you are a kind-hearted individual, it can be easy to find yourself getting taken advantage of by family members and friends who will walk over anyone to get what they want. You might see the best in everyone, and never think that someone you’ve known and loved for decades upon decades would betray you by trashing the house you let them live in for free when they’re going through a difficult period of their life. Unfortunately, you can’t always predict when somebody will take advantage of you, so you have to be the one to protect yourself first. 

If you’ve been burned once, you’re much less likely to be burned again. If someone lets a drifter friend of theirs sleep on their couch for 6 months and discovers that they’ve been stealing money from them the entire duration of their stay, there’s a good chance they won’t let anyone else stay over at their house for a prolonged period of time like that ever again. They might trust their college-student sister or their chronically employed cousin more than they trust their «friend,» but they know that if they make the same mistake twice, it will be unequivocally their fault this time. 

Even if you know that someone cannot be trusted to live in your home rent-free without trashing the house and making the house’s residents’ lives miserable, it can be challenging to say no to someone who is desperately begging for help that you aren’t going to give to them.