I'm very protective of my clothes and accessories so I never lend them out to anyone except to my sister and my mom. I think you should do whatever you feel comfortable with. It is ok to say no to your friends.
I totally agree. I never lend out anything to my friends. I dont' think that it's because I'm selfish, but over past experiences I've found that people are just inconsiderate and do not take care of the piece of clothing because it's not their own. It's definitely important to make it clear to your friend that you are not comfortable with the situation--just because you're friends doesn't mean you have to share all your clothes with her.