[quickthrower2]

I am guessing you are scared because:

(i) you won't be able to access importing accounts e.g. bank accounts where your email is your gmail account.

(ii) you won't be able to see your old emails.

Solutions

(i) Buy a domain name and use that for your emails. Forward those to GMail initially but you can forward them to something else if you ever lose GMail access. Update all your accounts to this new email address.

(ii) Use Google Takeout to download all of your Google data, including your GMail.

[jolmg]

(ii) You can also download all your mail via IMAP(S). MRA (Mail Retrieval Agent) programs like isync/mbsync, offlineimap, and others do this. They sync, so you can run them regularly to download just the new mails and keep your backups updated. Whereas using Google Takeout would give you the whole thing everytime.