You should check your bike rims, brakes and tyres once a week. If they don't feel right, bring the bike to our shop, we can check and fix the problem free of charge for you. The static spoke tension needs to be sufficiently high (depending on your weight) so that when you ride over bumps, the pressure is spread more evenly over many spokes. It's more important to check the roundness of the wheel, the spokes must not be slack but don't over-tighten your spokes! you will damage your rim permanently. It may only need tightening an 8th to a quater turn in a year. If you have not done this before, ask someone who has good experience.
If you want to do it yourself then this excellent video below helps illustrate the main points about how to true your wheels: