Grips are an important element and often ignored at the amateur and intermediate levels. As the name suggests, you will likely struggle to find good grip with your racket has a damaged, dirty, or bad grip.
There are two main types of grips:
Base grips: This is the grip that comes with the racket. It is already wrapped around the racket’s handle and normally made from a more durable material. While it is perfectly ok to play directly with the base grip, it is often better to put up an over grip on top of it for added cushion and to protect the original grip.
Over grips: These do not come with the racket and must be purchased separately. They are also much thinner and do not last as long. Over grips are made from a soft cloth-like material which includes a bit of padding. If you tend to have sweaty hands when playing, look for over grips meant to prove more sweat absorption. If your hand is normally very dry, you may want to go for grips with outer padding aimed at providing traction.