Your bow string will need regular maintenance much like any other part of your archery kit - it pays to maintain it and keep up with the wear and tear. The simplest thing you can do to maintain a bowstring is to wax it. How often is down to you, your climate, what type of terrain you shoot in for dirt build up and how often you shoot. Your string should always have a slight tackiness to it. If it feels dry or has a slightly hairy feel to the fibres then get some wax on it.