Squealing A/C Belt

What is your question?

Every person I know has the same problem with this car. The when turned on, the A/C's belt causes a squealing sound when in first gear or reverse. It is a screeching squeal! After you get your belts changed it goes away initially, but eventually it comes back. I have read videos suggesting loosening a bolt, pulling on an engine piece (I forgot the name of it) to pull that belt tighter, and retightening the bolt. But I have not tried this on my car myself so I do not know if it caused a long term fix or not. Any advice?

What makes this problem better or worse?

When it is hot outside

How long has your 2006 Scion xB had this problem?

SInce I have had the car (bought in 2009).