These days some conventional battery aids have a battery gauge and an app. Here’s a screen on the app for my Oticon Real 312’s:
The battery gauge isn’t linear, so an indication of 50% doesn’t mean half the battery life remains. But the fact is there are indications of the battery expiring long before you get the warning beeps. For conventional batteries, I think the choices on this screen ought to be more like 80%, 60%, 50%, because in my experience 80% means the batteries will be gone in a few hours. Other brands or models may be diffferent, so you have to get familiar with your aids if you want to get the most out of the batteries. Even with these IMO too-low warning thresholds, you can check the battery level before a round of meetings, and change them if it’s below 80% or 70% or whatever level you think is appropriate.
So there is a middle ground between squeezing out every last drop, at the cost of being caught short, and being conservative, at the cost of throwing away maybe a dime’s worth or less of battery power.