"The Horny Goat" wrote

| Perhaps I'm doing something wrong but it's not always obvious in
| Thunderbird where it wants to do your backups which has led to my
| saving them on my c: drive which is unfortunate as that's my SSD and I
| have LARGE archives of e-mail going back before 2010 (I'm on boards of
| multiple provincial and national non-profits) and it's NOT obvious
| where one sets one's default directories (as in sometimes it changes
| from release to release and sometimes I just plain forget then have to
| spelunk to remember where they're set).
|

Don't you also back up off-disk? I like to
clean out excess email, then back it up to
secondary disk, then write that backup
periodically to DVD.

I also made myself a little HTA utility that
runs on VBScript and MSIs, to back up older
emails in a searchable database.

So nothing depends on a disk not failing and
here's always a recent backup in multiple
locations. Occasionally I also drop a DVD in
my safe deposit box. That might seem extreme,
but it's only about $70/year. I started using it
to keep customer records but ended up using it
mostly to keep disk image backups and data
backups. A copy of email files on C drive, when
the original files are on C drive, is not a backup.