If you have a treadmill it must receive regular maintenance or you may have a sizable repair bill down the road.
The deck and walking belt on your treadmill must be lubricated on a regular basis. A dry belt and deck lead to premature deck and belt wear, as well as increased friction which translates to a high amp draw on your motor control board. This typically results in an expensive repair requiring that the motor control board be replaced and also possible the tread deck and belt.
If you are a serious runner who runs every day, your deck and belt should be lubricated typically about every three months. This typically requires about an ounce of pure silicone oil of manufacturer-recommended lubricant each time.
For the average year-round walker and runner, about twice a year is sufficient. If you only use it in the winter, then perhaps just one-time lubrication at the beginning of your indoor walking/running season would be sufficient.
I am always glad to teach how to do this on a service call visit Belts and decks should be replaced when they begin to get worn out. This will also prevent a more costly repair later. They both should always be replaced at the same time.