Yeah, if use a flashlight regularly, one that can use both lithium-ion rechargeable and lithium primaries is the way to go, imo.

Whether it's AA and 14500, or CR123a and 16340, or 2*CR123a and 18650.

Have the rechargeables for daily use whilst can recharge them, and the primaries when can't.

It really is ideal to have rechargeables with lithium primaries as backup or in storage. I live in Montana where the ability of lithium to function down to -40 or so is pretty crucial.

I keep one maglite around and I use Ni-Hm D cell rechargeable batteries in it. I do not keep it in a car and I recharge it before significant weather events.

In your situation, I'd probably just keep a good quality primary cells (Duracell, Kirkland, and Amazon Basics are my go to) in the lights and replace them annually.

Pretty wasteful as the cells are probably fine after a year, so hopefully you have someplace you can consume them. Maybe a camping lantern you use regularly or something.

Powerex (Maha) still has some D listed
https://mahaenergy.com/powerex-precharged-d-10-000mah-2-pack/

Many thanx for everyone’s input. I already do use a battery tester and visual inspection 1-2 times a year. I also keep an extra set of akalines in a plastic zip-loc , as a backup.

Digesting all the input, I’ve decided not to go to rechargeable. It would be OK for my and my wife’s flashlights, but less access for my grown kids, who safety equipment I still attempt to monitor. ( sigh )

The idea of using Heavy Duty Batteries with alkaline back-ups is interesting. Does anyone know which brands are true carbon vs alkaline batteries?. Does it say so on the battery cases?

I also liked the idea of using either AA or CR-23s s with spacers instead of akalines. Anyone know we’re or what to Google to find such spacers ?

Yes, the best ones say "super heavy duty" right on the package. That's a carbon-zinc-chloride chemistry.

Looking on Amazon, there are all sorts of brands like Eveready and Panasonic (probably all made in the same factory somewhere).

It might be best to try them in one of your lights and see if you get the performance you want.

For the basic batteries, I'm a fan of the Energizer Max batteries. For rarely used devices, they're economical, and have a good life. They also have a no-leak guarantee https://www.energizer.com/about-batteries/battery-leakage.

When it comes to leaking, avoid the Duracell family. This includes the Costco/Kirkland, and Sam's Club store branded batteries, that are (or at least were) made by Duracell. I've had so many flashlights or other electronics damaged by Duracell brand batteries. Some batteries leak while still in the original packaging.

Thanx. Rethinking my last post, your solution seems viable and the path of least resistance.

Interesting! I had not heard of those. I guess I tuned out all things alkaline when I went to NiMH.