Hearing aids come with two power types: a replaceable battery or a built-in rechargeable cell.
Replaceable battery
A dead battery is swapped immediately — no waiting for a charge. But you need spares with you, and changing them takes fine finger movement.
Rechargeable
The device goes into a charger overnight and is ready by morning. No fiddling with tiny batteries — especially convenient if fine motor control is difficult. In return, you need to carry the charger when travelling.
Which to choose?
It depends on your habits: how often you travel, how easy small objects are to handle, how many hours a day you wear them. Discuss these with a specialist.