So , I went to Goodwill today, and there was a treadmill there, $20....it's a Weslo Cadence XT. It's good..it does the job...I can go for a walk without having to leave the house...but the thing is..I can only go 2.5mph...and .5 mile..whereas when i'd go for a walk outside the house, i could go for a mile...and just not sure how fast i was going. If you try to get the treadmill over 2.5 it slips bad, so i can't do that but I was curious...if I went at a slower speed and longer distance would it still be as good of exercise?

Any time you're moving instead of sitting in a chair, it's good! It sounds like the belt is slipping, which is probably why the previous owner donated it. All is not lost. You can google "treadmill belt slipping" and find a lot of information about lubricating it or tightening the belt. Also, you can google by using the name of the treadmill to get specific information. There are times when the belt is damaged beyond repair and needs to be replaced. If that's what happened, you can still use this $20 bargain to get some exercise when the weather is not cooperating.