not a direct user, but family & relatives are - and the #1 issue is the battery stamina? strength? idk what to call it.. probably durability/performance? (fyi, cars are from both BMW and BYD).

Just like our cell/hand/smartphone, after a while, the battery cannot hold 100% charge capacity.
The longer you use, the shorter/smaller the capacity becomes.

E.g: Your new phone fully charge can tahan 48Hrs, after 1year, a full charge probably lasts less than 24Hrs. Same thing applies to the EV cars, 1 full charge say supposedly 500KM, but now only gives sub-450KM per full charge. <- example only, don't ask me the nitty gritty (for now)