When a personal power bank makes sense
A personal power bank can be practical if you already own one and remember to charge it. It works well when you expect to need power during the day and can prepare before leaving home. Because you carry it from the start, your plan does not depend on finding a rental station.
That preparation is also the tradeoff. The power bank must be packed, ready and kept with your belongings. If it is forgotten or depleted, it cannot help in the moment. Your own device also remains your responsibility before, during and after the trip.
