the best toothbrush ever but wears out completely in years [SEP] excellent cleaning of our teeth great results when we get checkups and keeps our teeth feeling great it would get stars except you must replace them about every years they just slow down and poop out have had or of them i do run the battery down occasionally like the instructions recommend to keep the battery memory effect down from the manual to maintain the maximum capacity of the rechargeable batteryunplug the charging unit and fully discharge the handle with regular use at least every months your iphone does not recommend this if oralb braun wanted to they could use a cell phone type of battery ie lithium and the lifespan and power would be much better but no its just an old tech nimh hi says so on the unit so great brush but meant to wear out pretty quickly also the replacement brushes are very pricey they have to be about to dollars each