[Open-Sourcery]

From one domain to another (gmail.com to custom), a bit of faffing about to get all the accounts moves over.

Moving the mails was as simple as ctrl+a and dragging my mouse in thunderbird.

Between providers with a custom domain (zoho to mxroute) was easy. Just updating the DNS records and moving the emails.

If you are technically able (really just buying a domain and setting the DNS records the provider tells you) I would recommend getting a custom domain. It gives you the ability to move providers at will pretty easily, even if you did want to stick with a gmail for now.