Keep your bike clean to preserve the life of your moving parts, including drivetrain components and fork/shock stanchions. Removing grit, grime, mud and dust on a regular basis will keep your bike shifting and performing well, and frequently wiping down your fork and shock stanchions and seals will reduce maintenance over the long run (click here to learn more from Tani about stanchion maintenance).
It's also a good idea to use as little water as possible when cleaning your bike. A better way is to wipe down the frame, rims, hubs and cockpit using any number bike wash products (come and see our selection). If mud has dried, use a soft brush to knock off large clumps, and a damp rag to get the rest. If water must be used, use it sparingly, at a very low pressure and try to avoid spraying areas that contain bearings or seals (bottom brackets, pivot points, fork/shock, dropper post).
Regularly wipe down your chain and other drivetrain components for better shifting and less wear and tear. A little preventative maintenance will also mean you'll have to deep clean less often.
Click here to see a great detailed guide Cycling Tips put together on how to clean your drivetrain.