I had a Weslo treadmill from Walmart and used it for many years, usually to warm up for 10' before heading outside. The belt and deck were always fine, even though I never put lube on the deck.
Eventually I got a well used Landice L7 treadmill for $750 from Craigslist, including paying the guys who moved it in their truck, and sold the Weslo one. A couple of years ago the Landice belt started sticking and grabbing on the deck.
I started lubing the deck and that helped but it still kept grabbing and sticking, so I found out the Landice deck is reversible and ordered a new belt. Lubing the deck again a couple of times in the meantime helped the belt to flow smoothly again so I've not yet changed the belt, but have the new one ready to make that change any time.
Whenever a belt wears out, make sure the deck is in good enough shape to handle a new one, or else you'll need to get a new treadmill. If the deck is still okay then make sure to lube it well before putting on the new belt, and make sure the lube is compatible with the deck and the belt.