Treadmill preventive maintenance begins when you select a permanent location for your unit.
First, you will need to make necessary adjustments to assure your unit is level before your first workout.
Most manufactures have adjustments to compensate for an uneven floor.
Check your owners manual if you can not locate them visually.
Use a level, don't trust your eyes.
There are costly circuit boards in your Treadmill, to protect these electronic components, the treadmill must be plugged in to a surge protector and a grounded AC outlet.
I suggest a Treadmill Floor Mat.
Not only does the mat protect your carpet or flooring.
It keeps dust and debris from being inhaled into your Treadmill while in use.
Lint and Dust may produce a static charge.
Treadmill Mats can be purchased online, form a local Sports Store or from the manufacturer.
One of the biggest reasons of Treadmill Failure is dirt, dust and pet hair.
When I make service calls, I am always amazed at the dog or cat hair I find under the hood or between the belt and deck.
All these contribute to premature failure to your investment.
Below are some tips for extending the life of your machine.
Always unplug your Treadmill and let it sit for at least 10 minutes before performing any maintenance.
This will give the transformer time to discharge, avoiding possible electrical shock.
Weekly Cleaning and Maintenance:

• Keep the area around your unit dirt and dust free
• Pull a damp towel between the belt and deck, rotate belt and repeat
• Clean and disinfect all handrails and /or grips and traction strips

Monthly Cleaning and Maintenance:

• Remove Hood
• Vacuum all foreign matter, this reduces wear and tear on motor and belt
• Check motor drive belt for wear and adjustment

If in doubt performing treadmill maintenance, you should contact either a reputable repair company, your dealer or the manufacturer for details.
The owner's manual that came with your machine will give you information pertinent to you piece of equipment.