I’ve been using a pair of Lumity rechargeables for more than a year now. Recently, been thinking about getting another pair of Lumity aids with replaceable (312…??) batteries as a back up pair to use on occassions when there isn’t time to charge up the rechargeables. Also, it seems almost all the audiologists in my area are pushing rechargeables; so it sounds like a good idea to get a pair of battery aids, as a long term backup. I understand the replaceable battery aids can be kept as backups for quite a long time. But my present audi is against the idea. He thinks I should wait a little longer to get the Phonak Spheres & then keep my present rechargeables (post servicing), as backups.