When Should You Clean Your Vacuum Cleaner?
Don't allow dirt to just sit in your dust bag!

You regularly use your vacuum cleaner to make sure that your floors and corners and spic and span, but when was the last time you cleaned this helpful tool?
After every use: Clean your dust bag/container
You might think that it isn’t really necessary to take out the dirt and dust from its bag or canister, and that’s actually a bad habit you need to change. Every time you use your vac, you have to empty its container, whether or not its full. A study featured in Web MD says that older and cheaper models that are not regularly cleaned actually spew back “fine dust and bacteria” into the air, so don’t keep the dirt sitting in it for so long. (That being said, you may want to invest in a newer vacuum cleaner which has its own HEPA filter.)
After every use: Clean your brushes
Your dust bag isn’t the only thing that you should be cleaning, though. You’ll also want to clean your vacuum brushes after every use. It’s pretty logical—no one wants dust bunnies and strands of hair nestled in between bristles. Keeping them clean also keeps them ready and efficient for the next time you use them.
Every month: Clean your filters
According to HGTV, there are different kinds of vacuum filters. Bagless or canister cleaners usually have foam filters, which is used to catch dust. Upon taking out the canister, you can easily see and pull out the foam, which you can then submerge in water (soapy, if you choose, just as long as you rinse it well) to get the dirt out. Air dry it completely before refitting it.
Some cleaners are installed with disc filters, which are easy to clean with water. A cartridge filter (which is cylindrical with pleated ridges) is usually disposable, but you can extend its life by simply tapping the dust and debris against your trash bin. Do not soak it in water.
RL Tip: Never clean your vacuum cleaner’s HEPA filter. Buy a new one if you feel that what you have is already spent.
Can you disassemble your vacuum cleaner for a deep clean?
It really depends on what kind you have, and if you still have the manual (you wouldn’t want to suddenly have an extra screw after reassembling the whole thing). Real Simple recommends a deep clean every 12 to 18 months with a can of compressed air, as well as replacing your machine eight to 10 years.
H/T: Real Simple