That’s the nice thing about lights that can also take a pair of ’123s. While pricey, chances are they’ll still be around for a while.

And even as Li cells age, capacity will decrease, discharge current will decrease, but plenty of low-stress lights can still use ’em just fine. I use laptop pulls in headlights, ferinstance. They don’t draw more’n 1.5A or so, at least the ones I have, so they should be fine for quite some time.