Interesting. Been in electronics since about 1954 and never thought much about how long capacitors last. They do fail and get replaced when they fail. Never replaced them before they fail. I guess having a supply on hand is a good idea. Seems to me a capacitor that is guaranteed to last 10,000 hours is a little over 1 year. I just changed out a cap in a piece of equipment I bought new in 1992. That is 23 years. I do agree when it failed there was down time. So guess I don't understand your logic changing out them out before they fail. BTW Mouser electronics does sell parts with mil specs etc.
