This kind of use is common and falls into the category of personal use as far as I can tell. My mother-in-law just got a computer for the first time and is a complete novice, so I help her out once in a while when she’s stuck. I also have it set up on my wife’s PC and my son’s PC so that I can get access from my office if they need help with something. Personally, I have TeamViewer set up on my work PC, my multimedia PC that I use for video and audio production, and my home pc. For commercial use, where you are charging money for services related to TeamViewer’s use, then there is a lifetime license that you can purchase. For most of us who use it just to access our various computers when we’re away from them, this software is completely free of charge.
TeamViewer is one of the best remote control software programs that exists today.