I guess rechargeable batteries have come along at about the same rate, now that I think about it. I haven't brought extra batteries for years.

My new light has the ubiquitous mini-USB, so I suppose I'll have to have to nab a little battery bank, which will also be useful for my phone on longer trips. I do have one now, but it's ...a flashlight. And a bluetooth speaker, which I wouldn't use in the woods anyway.