Ahh Jesus.
Compared to re-chargeable hearing pro, your replaceable battery-operated hearing pro lasts a long time.
Size 10 batteries, which my current pair use, should last you about a week, if you get shit off brand batteries they may not, you may only get 4 days, but what does one charge get you with re-chargeables, usually say, 10hrs.
Size 13, which my Walkers elite pro digital behind the ear used, would last about 2 weeks.
A case of 80 batteries for my size 10 cost me about $17, that's about 40 weeks of continuous operation of the devices. All those batteries can fit into near no space and are nothing to carry, in case you wish to carry a ridiculous supply on you. (Just don't remove the stickers, that activates them and they'll wear out from that point on)
You can buy the batteries on Amazon, you don't need magic batteries, but I do stick with name brand. My last couple cases have been Rayovac, like I said, last case of my size 10s was about $17.
Yes, the battery doors are small and fragile, they're hearing aids, of course they will be. Yes, the batteries are small, yes, they have tools to help if you should need.
I don't tend to baby mine, but you do need to treat them as though they are what they are.