Comment by colechristensen

>The point of failure for all of these machines has been the SD card. They seem to last 4 years almost to the day. I suppose if I set up a RAMdisk they might last longer, but honestly, for the price of an SD card it’s not really worth my time.

There are "Industrial" SD cards which should last considerably longer, you can look up a few people have done their own testing. They can be slower but that shouldn't be a blocker for an email server on a pi.