Ways to evaluate risk of a stock dropping to a certain level?

I was wondering what methods you all might use to evaluate risk of a stock dropping to a certain level? I've been using bull put spreads lately but have yet to carry one to expiration, as I have been paranoid that they might pullback to my strike just prior to expiration, so I have been exiting early(though at least with profit so far). However if I had just held on to expiration, they would have been 100% profit. So I am looking for ways to evaluate risk of not clearing the expirations OTM.