I have a 20 year old GE electric dryer that I have never had a problem with until this week. There is a very high pitch squeak. It usually starts a few minutes after the dryer starts.

Is it worth repairing, or should I just consider buying a new dryer?

Consider a DIY project that includes replacing some parts. One of these is the likely culprit. It is not hard to do at all and gives you an opportunity to clean out the lint in the vents (you'll be surprised by what you find). This will lessen the chance of an accidental fire as well. I did this myself recently. Pretty easy...

Order the appropriate dryer repair kit, just Google it.

Includes drive belt, both drum rollers, idler pulley, and the 'tri-rings' that retain the rollers.

Should be under $30 or so plus shipping.

Good luck.