The answer to 'how to maintain vacuum' is to regularly clean and maintain your vacuum cleaner to keep it running efficiently. This includes emptying the dust cup or bag, cleaning the filters, and checking the brushroll and other components for any blockages or damage.
It's recommended to empty the dust cup or replace the bag after each use, and clean the filters every 3-6 months. You should also check the brushroll and other moving parts for tangled hair or debris, and remove any blockages. Additionally, it's important to replace the filters and belts as needed, typically every 6-12 months, to ensure optimal performance.