I was diagnosed with moderate COPD 3 years ago. I don't have shortness of breath and don't use inhalers or oxygen. However, I'm going to Denver next month and since it's higher elevation than southern California, my doctor suggested I take a "rescue inhaler" just in case.. I read somewhere about a nightmare inhaler that uses capsules and they break, but forgot which one that was. And I also read somewhere that inhalers expire in a month? Is that a month after opening and using or what? Thanks:)