Backups of emails are OK, got a few of them. It's the constant need to receive emails as others have noted below is my fear.

If I'll get locked out will I be able to reset my password to the other bank account I almost forgot about? How long will it take for my old recruters to figure out not to mail me there? etc.

I run Thunderbird sometimes on desktop to cache all emails locally. I also have a NAS wich is downloading emails 24/7 and I can browse all locally from backup. This also gets backed up to 2 other locations :)

Search and find old emails.. that's where gmail works. I guess that's why I keep using it. For work I use Thunderbird (the best of the bad alternatives), and search is horrible and extremely slow (and usually never find what I want to find). If I had something which was as easy as gmail for handling tens of thousands of emails I would switch.

People constantly bash on thunderbird search, when it is actually the opposite.

Gmail will often fail on exact-match searches. Unbelievable frustrating and next to useless.

Thunderbird is a bit clunky but does what you ask of it and has much better+simpler filtering options.

Which makes sense, gmail is in the cloud so it can't perform intensive search queries because that would cost way to much.

Thunderbird has a dedicated machine for it, no matter how old and slow it is it will have way more resources at hand than google will ever allocate to you, even if you pay.

I use Thunderbird but I only do so as it's the best of a bad lot (before that I used Eudora before Qualcomm dropped it - Eudora users know everything else is a letdown).

Thunderbird has forks but they too need much work. The trouble with email started when free email was included in Windows thus taking the incentive away from development. Same goes for Thunderbird nowadays with free Gmail being available.

I was working in a College's IT Dept when they were migrating everyone from Eudora. Lots of the professors were of the "You can pry it from my cold, dead hands" opinion. They often had 10s of gigabytes of email dating back to the early 90s, some even earlier.

Yeah, and converting old mail wasn't easy even when Thunderbird had an importer. 10s of GB were a problem as the importer often broke at about 2GB. Even TB's own native boxes broke when about that size.

So could Eudora's for that matter. Crashes were a particular problem with large boxes (.MBX files) as they often had crosslinks from users shutting down too quickly. Trouble was that when the mailer reindexed/compressed the box it would often stop at the crosslink and the remaining mail lost (I used to advise everybody never to reindex unless they'd backed up immediately beforehand). No doubt if you were in the IT at the time then I'm preaching to the converted. ;-)

I often use this example to illustrate bad design and the need for data hardening. If the time you're mentioning was before Qualcomm announced an end of Eudora then this may have been one of the reasons to move away. That said, mail clients haven't progressed much since. The MBOX is simple and still predominates but that's a mixed blessing when we need separate index files. Essentially, those who've many GBs of mail still have a problem. Little wonder many have turned from POP/IMAP to web mail.

I was wondering the same thing, I have quite a few years of email in Thunderbird and I generally find the search to be very effective.

Apple's Mail.app I'm using does a good enough job of searching emails.