I have used hairspray every day for a loooong time and it hasn't damaged my hair at all. The surest way to get rid of split ends is with scissors (!) and use as few heat appliances as you can. The more you let your hair airdry, the less it gets damaged. I think the best thing anybody can do for their hair is to invest in a good haircut that works with the hair's natural movement, so you don't have to force it with a lot of products and heat. Easier said than done, I know.