Hear a squealing noise when I turn ignition key on my 2000 Toyota Echo. I've learned how to stop the squeal sometimes if I quickly turn the key, but sometimes it still squeals. Had a mechanic look at the belt and he said it still looked OK. Can the belt be tightened or loosened to stop the squeal or should I just have the belt replaced? I bought this car last November so I'm still getting familiar with it and I don't know when the belt was changed last. Trying desperately to save money, but it's my only car. Any advice would be appreciated. Thanks
It's easy to replace the belt (and not expensive) See this diagram. One wrench, and you don't even have to adjust anything - there's a spring that adjusts the tension .But it may be the tensioner bearing. Don't go to that mechanic again.

Who was the mechanic, Stevie Wonder?