DISQUS

I too would rather have a rule set an expiration date for inbound, but this is what I do now. Create a fold named something like "Compost" > create sub folders suchas as "Days 001", "Days 030", "Days 365" and so on (I use 1, 3, 10, 30, 90, 365.) > apply properties to each folder for AutoArchive permanently delete after xxx days > Create rules for received mail to deliver to to the appropriate compost folder. > and turn on autoarchive.

This autoarchive folder, the rules to put mail into the folder, plus search folders make the folders accessible by relevant subject yet delete them automatically.