How long can a bluetooth headset be used without charging

Because the app does inform you only a few times in a hour, is the standby time of a bluetooth headset important or the possible speaking time ?
So if they say this headset can be used for hearing music for 3 hours, but has standby time for 12 hours, can i use it for navigation about 10 hours ?
The idea is to use a cheap in ear headset without any quality for music but good enough for understanding a navigation programm.

hmmm - if you drive from Munich to Berlin on the “Autobahn” …

Don’t know how long my (BMW)-Communication System can be used for music (not hearing them on a bike), but after a whole day (~10 hours) it says “Batterie is low”.

If the headset in question goes into standby, when there are no instructions, then this could work. I think no one will be able to tell you for sure without testing.

It is always possible to charge your equipment when you pause, for example during lunch. Most devices nowadays charge pretty fast.