I have a whirlpool dryer which is approx. 12 years old and used 2-3 times per day. Within the last 2 weeks its developed a high-pitched, extremely annoying squeak. At first the squeak lasted only 2-5 minutes into drying, now its constant and getting louder with each use. I am not sure if it is worth it to invest in a new dryer or repair this one. We'd actually like a new dryer with the Steam feature to save on weekly dry cleaning costs, but don't want to get rid of/ donate a perfectly good one if its an easy fix. Can you advise me please?

2-3 times a day?? Serious? It's a miracle that your machine did not give up earlier...
Do you perhaps manage an orphanage?

:)

You have to do a little research here. To check what is going on in your dryer here is a general check procedure : in your case just check the drum "gliders".

Remove the rear panel, and have a look as to what is going on.
Check the drive belt : is it frayed?
Is the drum running against something?
Does anything look lose or broken?

Please be careful : do not touch anything while the dryer is connected to the power.

If you can not find anything, remove the power - take the power cable out of the socket and put it on to the ground.
Note down how the belt is connecting the drum and motor.
Remove the belt (by taking away the tension from the belt this is easy).
Spin the (empty) drum a couple of times by hand, as fast as possible. Is it running freely?
Spin the motor a couple of times by hand, as fast as possible. Is it running freely?

This procedure will allow you to research what is the problem in your machine.
If everything seems fine your problem may be related to either the drum bearing or the teflon "gliders" between the drum and the door window.
These gliders can be replaced. A faulty drum bearing means a brand new dryer...

Of course you can also come back to the board and discuss your findings!

Success !

:)