How long do one of these typically last? We have one that's nearly 7
years old and has stopped heating. I suspect the magnetron is gone.

Given that it will cost at least $ 100-150+ to repair, should I bother
or replace it? Hate to create more toxic waste...

Thanks

The magnetron is a possible cause of the non-heating and that would
make repair cost prohibitive. It is also as likely that the diode
connected between the capacitor and ground has failed and this is a $5
part. A knowledgeable person can diagnose whether it's the transformer,
diode, capacitor, or magnatron in about five minutes after removing the
cover.

I'm going by you description that it seems operational except for the
fact that it is not heating. The touchpad works. It lights up and just
doesn't heat. This suggests a failure in the secondary, meaning the
parts noted above.