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 bow string is to wax it.
How often you do that is down to you, your weather climate, what type of terrain you shoot in for dirt build up and how often you use your bow. 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!
How to wax a bow string
Applying wax is very simple. Most bowstring wax comes in a tube or block. String up your bow and then rub the wax into the string until tacky. Grab a piece of leather or a soft cloth and run it up and down the string. The friction will melt the wax into the string fibres.