(Obviously if its not plugged in, the battery will drain. If you wear them to work daily (I work outside at a retail plant nursery), they will last almost a year before they start to tear up/sole separating. Every pair of shoes he has is the same size as these yet these were the most difficult to get on his feet and they really wouldn’t stay on. The left slipper was pretty wide but the right one was so wide my foot went right through it so my toes were hanging over front edge, leaving a huge gap behind my heel - and I have wide feet. These were exactly what I wanted. I tried some songs from you tube and that led me to put up to date my smart tv, which I hadnt used it that way before. Very comfortable but squeaks when I walk. This headset works great with my Ps4, played right out of the box. Dont worry about focus, as your eyes stay set to "distance" because you are looking at the cars/bikes/pedestrians way behind you, not the actual mirror! Not too hard to figure out how to insert the batteries, there are green arrows "pointing" the way.