Regular maintenance will keep your vacuum cleaner working at it's best capacity for a longer amount of time and will also help it to last longer.
The first step is to be sure that your vacuum cleaner is unplugged. Then you will want to go over your vacuum cleaner's instruction manual as each is slightly different and we will just be giving a basic guide, you will want to be sure that your vacuum doesn't need more or less than what we suggest. If you cannot find your vacuum's manual sometimes you can find a .pdf online when doing an internet search of your vacuum brand, model number, and then the term manual with it.
On a regular basis you need to check the service ports and hose to be sure there are no obstructions in your vacuum cleaner. Also you will need to check your HEPA filter regularly as the indicator for checking it sometimes fails on the vacuum cleaner. Not changing/cleaning your filter in a timely manner can cause the motor in your vacuum to burn out and also causes a very real fire risk.
If your vacuum cleaner uses a bag, be sure to check it frequently and replace when it is 1/2 full. If your vacuum doesn't use a bag, empty it when the instruction manual suggests, or if it makes it easier on you, empty after each time you vacuum to make it easier to remember. Anytime your vacuum is losing suction, check your bag or canister first to be sure it isn't too full to work properly.
Don't forget that the roll brush on the bottom of your vacuum cleaner also needs to be cleaned regularly. When cleaning the roll brush, be sure to check the belt to be sure it doesn't need to be replaced, a belt that has cracks, worn spots, melted places, or is uneven needs to be replaced.