Probably something easy

It's as simple as copying the profile folder. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

can I go to a POP3 client?

When you're running Thunderbird you already have a POP (capable) email client.

bretthenryjames said

I can't find any memu option to back up my e-mails. Probably something easy but I was born last century.

Thanks for that Christ1. I believe that is where they are stored. Can I do a manual backup from a Thunderbird option? I am worried of a hard disc failure. Or would it just be easier to include the profile files in my computer backup?

Thanks for the info on Pop3. I believe that Pop3 sucks the e-mails from the internet onto your hard drive and that is it? ie Synchronisation is not happening all the time???

use this add-on https://addons.mozilla.org/en-US/thunderbird/addon/importexporttools/

would it just be easier to include the profile files in my computer backup?

Backing up the entire profile would be the recommended option.

Pop3 sucks the e-mails from the internet onto your hard drive and that is it?

That's basically what POP does. There is an option to leave messages on the server though.