Thanks for the reply.
I guess my question could be better stated. I'm looking at a two CR123A powered LED light for use as a weapons light on a rifle. The light would rarely be used (hopefully never!) So, should I put in the batteries, untested, and trust their stated shelf life (so as not to "partially discharge"). Or do I test every month or so for just a few seconds per test, and then replace no matter what after, say, 5 years?
Also, does "shelf life" only refer to "totally unused"? If the cells are tested for a few seconds every month, does that by itself kill their long shelf life? Since they're no longer "on the shelf", technically they're "in use" - just "very little and very infrequent use"?
What I want most is reliability over a long period. I don't want to reduce that reliability by doing testing that might actual reduce the reliability over time by partially discharging. I plan to buy top-tier US made batteries, always as a pair (same package), and always install/replace as a pair.