The suction of a vacuum cleaner should not decrease significantly if it is left on for long periods of time without being used. Modern vacuum cleaners are designed to maintain consistent suction even when they are running idle.
Vacuum cleaners operate using an electric motor that creates the suction to draw in dirt and debris. When the vacuum cleaner is turned on but not actively vacuuming, the motor continues to run, but it typically operates at a lower power mode or idles to conserve energy. This idle state should not significantly affect the performance or suction capability of the vacuum cleaner.
However, leaving a vacuum cleaner on for extended periods without using it can waste electricity and potentially put unnecessary strain on the motor. It's always a good idea to turn off appliances when they are not in use to save energy and extend their lifespan.
If you notice a decrease in suction over time, it is more likely due to other factors, such as a clogged filter, a full dustbin, or a worn-out brush roll or belt. Regular maintenance, including cleaning or replacing filters, emptying the dustbin, and checking for blockages, will help ensure optimal performance and suction of your vacuum cleaner.