Because of the work I do, I have an almost unlimited supply of half-spent lithium AA cells from my employer. We put them in dataloggers and run them for two or three years in very remote places (see two examples on the ETS map). We replace long before they are dead in case we can't get back for a year or two.

Recently, we've started using new loggers that take 123 cells, so I'm now in the market for a new LED flashlight that takes these. So far i like the look of the Pelican M6.