car trailer advice

All good advice here.

I have a problem with people borrowing "my stuff" thats ok... but! It upsets me when I go to use my trailer and the last person knocked a light off or worse yet tore the trailer plug off. My buddy always says I have a problem saying no so he handed me a dollar and said....now I am a co-owner of the trailer and don't lend it out without my permission. And he never says yes. As for him... He has his own trailer and anytime he borrows something of mine it comes back in the same or better shape.