One of the greatest dangers that can befall any camera is letting it remain in storage for long periods of time, unused. Inactivity can cause the lubricants to dry out and the rubber and fabric materials in the camera to rot. Even if you don't take pictures, take the camera out at least once a month and operate it several times. If you have a camera with variable shutter speeds, run it through all of them.
If you know that your camera will not be used for a period of a month or so, remove the battery. This will eliminate the possibility of battery leakage ruining the camera. It will also prolong the life of the battery.
If at some point you feel that your camera isn't working the way it should, never, ever attempt to repair it yourself. Never try to use any substance such as WD-40, or anything else, to lubricate any part of a camera that seems to be sticking. Attempting to make home repairs on a camera, or waiting too long to have problems checked, can result in potentially fatal (to the camera) problems.
As a general rule, if your pictures look good, don't have your camera checked for possible repairs. Just taking the camera in to have it looked at can be expensive, even if no servicing is required. On the other hand, be sure to take it in at the first sign of trouble.
But don't be too hasty. When your camera begins to act strangely, the first thing to check is the battery, or the camera's battery check display. The battery might need replacing, or it might just be that the battery contacts need roughing up. Remove the battery and use a pencil eraser to rub all battery contacts, those on the battery and those in the camera. If this doesn't help, replace the battery with a new one. Incidentally, use only high-quality batteries in your camera. Cheap batteries will be less expensive, but they also have a much shorter working life, and will cost more in the long run.
Although your camera will last longer if it's used on a continuing basis, it is also not wise to operate any of the camera mechanisms unnecessarily. Operating the zoom lens back and forth when there is no need to can cause excessive wear on the zooming mechanism. It's also hard on the camera's battery and the motor.
If dirt and dust settle on a lens, the results can be fuzzy pictures. If they settle inside the camera, the result might be no pictures at all because they can jam up the camera's mechanical system. At the first sign of dust or dirt, get rid of it. Trying to blow it out can force the stuff further into the camera.
The best way of getting dust and dirt out of a camera is vacuuming it out. Here's how to make a homemade vacuum cleaner. Take an old ball-point pen (Bic works best), and remove both ends so you have a hollow tube. Next, cut a two-inch circle from an old, well-washed man's handkerchief and place it over one end of the tube. Hold the material in place with a small rubber band or a 5/16 inch rubber O-ring.
To use this device, place your mouth over the open end of the tube and the other end near a piece of dust and inhale. To expel the dirt, turn your head to one side, with the tube still in your mouth, and blow.
By taking reasonable care of your camera, and using it frequently, it will give you many years of service. If the unforeseen should happen, be sure to take the camera in for repair, and give the clerk all the details. Okay, how long has it been since you last operated your camera?