Cleaning your camera and lens is very important part to take care of your equipment and it helps to produce good quality picture consistently. Even small fingerprint on the front glass of lens can impact on the quality of photos. How often should you clean your lens and camera, it all depends on how often you shoot and where do you shoot. For example, if you shoot a lot in beach area where sands and dusts are present, you may have to clean your lens for every next shot and your camera sensor more often than people who shoot inside studio.
It’s very strange to accept the fact that lots of photographers, who own expensive lenses and camera body, never pay attention on cleaning their tools which help them capturing stunning photographs. If we take good care of equipments, our equipments take care of us. Personally I clean up my equipments every time I come back from shooting and before storing it to dry cabinet. It is also very common for photographers to use UV lens in front of their lens so that actual lens won’t get accidental scratch and they don’t have to clean their lens every time and just cleaning UV filter will do the job.
You can use microfiber towel to clean the lens body and front glass which doesn’t leave residue on the surface. Don’t try to clean your lens or camera sensor with rough surface material like normal towel or napkin paper; you may permanently scratch front glass of the lens if you use hard surface material. I don’t recommend cleaning your sensor unless it is covered with dusts and you are experiencing problem with the image quality. Cleaning image sensor by yourself without having proper knowledge may destroy your camera permanently. Some DSLRs (Nikon D90 for example) come with the option that will lock camera mirror up and allows you to clean the sensor using blower or other cleaning tool provided by camera manufacturer or other individual company who produces quality accessories for camera.
If you go to SETUP MENU by using MENU button the back of your D90, you will see option called “Lock mirror up for cleaning” which is specifically designed for photographers to clean up sensor if in case there is a dust. You can use this option to raise the mirror and open the shutter so that you will have access to the sensor for cleaning with a blower, brush, or swab as shown in the picture above. You can find those lens cleaning kit online for $20 or less. Nikon D90 allows you to use this feature only when your camera has a fully charged battery or sufficient battery for cleanup because you don’t want to power to fail while you are cleaning your sensor.