great toothbrush replaceable nimh betteries you supply is way better than non replaceable nicad [SEP] i had mine for over years works like a charm it has been in luggage lots of times too i do not recall ever dropping it in a sink full of water or with the faucet running or dropping it into a toilet or a full bathtub or running shower so i cannot credibly deny the star review complaints i bought a bunch as gifts for my friend and his family and two of four the ones the kids used died in the first few months the stars is based on my personal experience just do not expose the battery end bottom half to more than a short modest spraying of water and it should last a long time for you you can buy of these for the price of the traditional model and works just as good get your heads in packs at costco much cheaper for the amazon wal mart price of yes the heads are expensive but if you do not have braces or whatnot you probably can push a month replacement cycle