i figure the main thing about lending bikes is making sure you are on the same page when it comes to fixing it up if there's an accident.
i remember a close friend saying cool, you have two bikes now so mind if i come for a ride with you? i said of course, i know you haven't ridden for years so as long as you don't mind fixing stuff if it gets broken.
she looked surprised and said don't worry about it. some lenders would not expect the borrower to fix their bike. some borrowers would expect a good friend to pay for their own mistakes. just pays to be clear or a friendship could go down the gurgler pretty fast!