You don't want a beard trimmer that only works when plugged in, certainly. How much juice you will need is dependent upon how fiddly your beard is. For anyone who is just trimming it all back to stubble each and every number of times, battery life isn't really that vital. https://bracesknee33319.theideasblog.com/23998332/an-unbiased-view-of-tyche-hair-trimmer-t-blade