take good care of the internal battery [SEP] i bought this trimmer two months ago i use it to keep my hair very short i have not gone to a barber ever since i bought this i simply turn the dial to set the guard to level and cut all of my hair the same lenght definitely easy to use on my short hair i can probably get four complete haircuts in one charge this is a good trimmer for those men who like to keep their hair very short all the way around use it two times and it would have paid for itself due to the fact that you were able to avoid going to a barberthis is my second norelco trimmer my first one was a that i bought back in february of the battery stopped taking a charge four months ago after almost years of use i called norelco to have the battery replaced and i was then informed that they do not replace the batteries on these trimmers since replacing the battery would cost as much as buying a newer unit so i ordered the newer from amazon the functions just like the older in addition the can also function as a corded trimmer in the event the battery stops taking a charge the service life of the trimmer can extend beyond the life of the rechargeable battery by using the cord i am satisfied with itby the way the reason why the battery got damaged in my older was that i kept the unit plugged in the charger stand for very long periods of time i later learned not to do that as that practice will damage the battery over time overcharging even a little seems to damage the battery over time it is best to read the directions so you will know how to properly care for the battery the battery basically will determine the life of the unit the cutters do not wear out from what i can tell the motor seems durable so the life of the unit is really how long you can keep the internal rechargeable battery working norelcos internal rechargeable ni cad batteries can last a long time if given proper care they seem to be of good qualityi had a norelco razor and the battery was still taking a charge after nine years the razor had the advantage of having a five level battery meter that tells you how much charge is left in the internal batteries basically you want to wait until there is only a little charge left before you put the unit in the charger it seems this trimmer is a bit different though the instructions on the unit say to completely drain the battery which would be a bit inconvenient with the trimmer it takes hours for a full charge recharge fully that way you can minimize the dreaded memory effect or voltage depression and extend the useful life of the rechargeable batteries the rechargeable batteries are permanently soldered inside the unit this trimmer unit does not have a charge meter i refrained from getting the pricier unit with a charge meter in order to economize however my advice to you if you are not too cost sensitive is to get a unit with a charge meter that way you will know when to charge the unit and when to remove the unit from the charger that precise practice should help extend the life of the battery and hence the unit