The first part is simple, regularly clean the machine after each use and once a week with a damp cloth to remove sweat and dust, especially the console and handrails.
Vacuum under the belt maybe monthly, and don't put the treadmill directly on a carpet, get a mat under it.
Also, lubricate the running belt with a silicon-based lubricant every 3-6 months to reduce friction. Friction is the enemy of a Treadmill!
You don't need a lot! Less is more here.
Periodically, say every 3-6 months, inspect and tighten all hardware and check the belt alignment to ensure it remains centered on the deck. Treadmills operate better and longer on a dedicated (5-20) circuit. Finally, ensure the treadmill is on a level surface and refer to your owner's manual for specific manufacturer guidelines
If the belt on a treadmill seems to be uncentered over time, an alignment might be the fix. This bit is from True's website.
If the running belt is too far to the right side:
- Locate the right side belt adjustment bolt at the rear of the treadmill. (To determine left and right, stand at the rear of the treadmill and face the display.)
- On the right side of the machine, turn the adjustment bolt clockwise ¼ turn.
- Turn the treadmill on and start the belt at 3 mph (5 kph) keeping off the unit.
- Allow 2 minutes for the belt to self adjust. Move the Belt to the Left Side Repeat these steps if additional adjustment is necessary.
If the running belt is too far to the left side:
- Locate the left side belt adjustment bolt at the rear of the treadmill. (To determine left and right, stand at the rear of the treadmill and face the display.)
- On the left side of the machine, turn the adjustment bolt clockwise ¼ turn.
- Turn the treadmill on and start the belt at 3 mph (5 kph) keeping off the unit.
- Allow 2 minutes for the belt to self adjust.
Repeat these steps if additional adjustment is necessary.