Most modern mice are wireless, which is a lot less of a problem than it used to be. Older wireless mice could be heavy and unresponsive, with batteries that needed changing too regularly. Things have improved, however, with better wireless connections and super power-efficient sensors meaning that the best wireless mice available today can often even outperform wired mice and can run weeks or months before needing a recharge or a fresh battery (although of course with wired mice, you can forget about batteries completely.)