Wore them for at least 10 miserable years. I wouldn't recommend unless it's only a temporary or occasional requirement. My eyes were terrible, they were able to get me to where I didn't need a waiver for 1st class. A couple of years ago I had a small chip in the edge of one and went to the Dr., he started me on a series of soft disposable lenses and let the ortho-K correction deteriorate back to a stabilized condition, (about 6 weeks)then glasses for about 4 weeks until I had LASIK done. I don't think you could do it if you're planning for the military, but I feel that it's the single best thing I've ever done for myself. I can see all of the time, 1st class without correction or squinting and I don't have my fingers in my eyes or contacts in my mouth anymore. Wearing contacts is definitely not risk free as critics of the LASIK would have you believe.