Most microscope problems occur as a result of improper handling. When carrying the microscope, always hold it by the base and the metal support arm. Do not pick it up by grabbing the stage, as this can cause mis-alignment for the mechanical stage. If you will be transporting the microscope frequently from one location to another you might consider purchasing a microscope carrying case. Dino-lite Handheld Microscope Pro is an easy to use, low-power microscope.
When the microscope is not in use keep it covered with the dust cover. This alone will extend the life of your microscope. Even if the microscope is stored within a cabinet, you should still cover it with the dust cover. Do not store a microscope without any eyepieces, even if it is covered. This can allow dust to collect within the eye tubes, which can be difficult to clean. If the microscope eyepieces must be removed, simply cover the tubes with caps or a plastic bag with a rubber band around the eye tube.
If you are using immersion oil the high power objective lens (usually 100 xs) and the lens of the condenser should be thoroughly cleaned before storing. After using the microscope, turn off the illuminator and wait for it to cool for several minutes before putting it away. By allowing the bulb to cool you will extend its life. Also, make sure you do not store your microscope in an area that has corrosive chemical fumes that can destroy lenses or metal parts.