If I'm in a class or quilting circle & don't need something, I will share. I have been blessed to be helped by others when I didn't have everything I needed and am happy to pay it forward. I don't think I would share my machine, though. It took quite a lot of time to figure out how to properly use it so that's probably the one thing I wouldn't share (and I definitely refused to share my freshly sharpened Gingher's with someone who didn't understand why I asked to borrow a pair of paper scissors from a classmate to cut pattern pieces).
I share certain supplies with my nieces when they come over. They are adorable & only 2 and 3 years old so obviously they don't have their own stuff. They're helping design a little receiving quilt for their baby brother/cousin. So cute!
I would not lend out my supplies for someone to take with them. It's too hard to keep track of them & there's no way I'd know if they were caring for them the way I care for my stuff.