Here are some hints and how and when you should do it!!!
How to clean a vacuum cleaner?
Empty the vacuum cleaner, discard the contents in the outside trash, and use an anti-bacterial wipe to clean the vacuum. Let it dry thoroughly. If your manufacturer says your vacuum canister is washable, wash it out with warm, soapy water and then rinse it and let it dry. Also, be sure your vacuum's hose and intake valves are clear and open.
1- After Every Use: Clean the Brushes and Bristles to ensure there’s no trapped debris or hair stuck to them. If there’s any hair or lose strings wrapped around a brush, don’t pull it: Use a pair of scissors to cut it out instead. Next, spray the brushes with a disinfectant spray to sanitize.
2- After Every Few Uses: Empty the Vacuum Canister rather than allowing your vacuum canister or bag to fill up do it this way every time you use it. At the very least, “empty the vacuum once it reaches half to two-thirds of the way full (make it a habit). This way you’ll be tossing out any potential germs or bacteria before they have time to take hold in your vacuum. By emptying the canister you’ll also be helping boost your vacuum’s performance.