bardsapprentice wrote:
We've lived in a home for 20 years that was built in 1970. It has
aluminum wiring.
snip
We've changed the switches in the kitchen and elsewhere and "pigtailed"
the switches.

I hope you didn't pigtail with purple wirenuts
http://www.inspect-ny.com/aluminum/ideal65.htm

This device seems better and is only slighty larger than a 'red'
wirenut
http://www.kinginnovation.com/products/alumiconn.html
I have no ties to King just passing on a _potentially_ better product.
There are also special switches and outlets that are designed for use
with aluminum wiring.

I agree with most of what has been said. If you are comfortable I
would pull the panel cover and check the tightness of the connections
in your breaker box. I also have aluminum wiring and tightened all of
the screws and less than a year later at least three were loose.

Lights will give you an immediate indication of a problem on a circuit
because it is visual. A toaster on the same circuit will give you no
indication of the same problem.