Treadmill belt getting trashed

Last night I was scheduled to run 8 miles: 1 easy mile, and 7 miles @8:00 pace. I started to run the easy mile, the belt was tracking poorly on my TM. It was rubbing against the side. So I got off, and decided I needed to adjust the belt.
I knew the front roller was slightly off causing the belt to canted. I hadn’t gotten the front roller exactly straight again after having the broken frame welded. Either that, or the thing shifted some.
I removed the motor cover, and adjusted the front roller, and then adjusted the back roller. I got it running fairly straight. There was a slight fwack, fwack, fwack as the belt went around. The belt is worn on the inside. I have put a lot of mile on this thing. I lifted the belt, and saw some loose pieces. I grabbed a piece of tape and stuck it over the loose pieces. I didn’t want them to catch and tear. This turned out to be a mistake. When I turned on the treadmill, there was a strange noise, and the belt went hard to the one side. WTF? I thought maybe a roller shifted. Nope. The roller grabbed the tape which then pulled the threads from the belt which then wrapped around the roller, which caused a fatter spot on the roller, which then caused the belt move hard to the left. With a knife, and pliers, I managed to get the threads removed from the roller. After a while and a lot of work, I got the treadmill running again. Now it runs like it had before, and the belt runs straight.
I may step up my search for a new treadmill. I am debating about whether to buy another cheap used treadmill, a new home quality treadmill, a used gym quality treadmill, or a new gym quality treadmill. I don’t particullarly want to spead $3000 for a treadmill. I paid $325 for the treadmill I am using now. I have put a lot of miles on it. I am probably doing a lot more on it than it was designed to handle. But at $3000, I can buy 10 of these cheaper used TMs. I only goes to 10mph (6:00 pace). But I was just thinking that for the days I need to run fast than 6:00 pace, I can always go to the community center and use their TMs. I think they charge a $5 fee. I don’t know. Hopefully my TM will last until I find a deal on another one.