I did pretty much a similar thing years ago, but went self-hosted. It took a year or so including the transition phase.
1. Set up incoming E-mail forwarding from mydomain.org to Gmail. Exim will do this, probably all popular mail packages support forwarding well.
2. Start sending E-mail (from Gmail's interface) as me@mydomain.org, and tell your friends to use that one.
2.5. (optional) Get your local mail client to work with Gmail's IMAP and SMTP.
3. Take a deep breath and change that MX record.
4. Block out one or two evenings, pour yourself some Scotch, and go through each and every online account you have, changing your E-mail address. A password manager helps with this because it's also the definitive list of every online account you have. While you're at it, you might want to use me+company@mydomain.com so you can tell which E-mails come from which company, and know who is selling your E-mail address around.
5. Wait until people switch over and the vast majority of your E-mail is going to me@mydomain.org instead of your Gmail address. For me this took a year or so.
6. In the mean time set up locally hosted E-mail at mydomain.org. In my case I use exim4+dovecot+spamassassin. Don't forget to set up SPF and DKIM correctly.
7. Pick a time in your life when you don't expect to be getting urgent or important E-mail, like you're not buying a house or applying for jobs. Take a deep breath, and apply the exim config that changes you from forwarding to self-hosting.
8. Ask all your friends to send you some test E-mails, preferably from different providers. Make sure you can at least deliver mail from gmail, yahoo, comcast, verizon, etc. Send mails to them and make sure they're being delivered.
9. Assuming no problems in 7, pat yourself on the back for being part of the solution rather than the problem.
10. Periodically keep your eye out for trouble. Audit your logs every so often to make sure you're not having trouble sending or receiving. I had to change my IPv6 at one point because comcast decided mine belonged to a spammer, but other than that it's been smooth sailing.
11. Decide whether or not to keep your Gmail account. I kept mine, but it pretty much only gets spam now. Maybe once or twice a year I get a legit one there from someone I forgot to tell I changed my address. I keep an eye on my Gmail to find out when there are hot singles in my area or that there's a new sure fire diet pill that sheds fat instantly.
I tried self hosting. And even with SPF and DKIM set up correctly my e-mails to Outlook.com (and assocciated other domains) was just dropped. It didn't go to the spam folder, it was just silently dropped. At the time I heard that this was essentially expected behavior for an IP without a good enough trust record. This even happened when I replied to mail sent from an Outlook.com account. Having my e-mail randomly not reach its intended recipient was and is still unacceptable to me, so I bit the bullet and paid for hosting on my own domain. And while I'm still not happy about paying for hosting that I have sufficient capacity for on my own servers, I have otherwise been happy with it "just working".
If there’s one thing I want an antitrust investigation to focus on, it’s the gradual monopoly that Google/Microsoft/etc have inadvertently built over “clean” IP addresses. It’s now practically impossible for independents and small businesses to run their own mail servers.
I’m not blaming Google/etc for it, but it is a situation that requires a fix.
1. Set up incoming E-mail forwarding from mydomain.org to Gmail. Exim will do this, probably all popular mail packages support forwarding well.
2. Start sending E-mail (from Gmail's interface) as me@mydomain.org, and tell your friends to use that one.
2.5. (optional) Get your local mail client to work with Gmail's IMAP and SMTP.
3. Take a deep breath and change that MX record.
4. Block out one or two evenings, pour yourself some Scotch, and go through each and every online account you have, changing your E-mail address. A password manager helps with this because it's also the definitive list of every online account you have. While you're at it, you might want to use me+company@mydomain.com so you can tell which E-mails come from which company, and know who is selling your E-mail address around.
5. Wait until people switch over and the vast majority of your E-mail is going to me@mydomain.org instead of your Gmail address. For me this took a year or so.
6. In the mean time set up locally hosted E-mail at mydomain.org. In my case I use exim4+dovecot+spamassassin. Don't forget to set up SPF and DKIM correctly.
7. Pick a time in your life when you don't expect to be getting urgent or important E-mail, like you're not buying a house or applying for jobs. Take a deep breath, and apply the exim config that changes you from forwarding to self-hosting.
8. Ask all your friends to send you some test E-mails, preferably from different providers. Make sure you can at least deliver mail from gmail, yahoo, comcast, verizon, etc. Send mails to them and make sure they're being delivered.
9. Assuming no problems in 7, pat yourself on the back for being part of the solution rather than the problem.
10. Periodically keep your eye out for trouble. Audit your logs every so often to make sure you're not having trouble sending or receiving. I had to change my IPv6 at one point because comcast decided mine belonged to a spammer, but other than that it's been smooth sailing.
11. Decide whether or not to keep your Gmail account. I kept mine, but it pretty much only gets spam now. Maybe once or twice a year I get a legit one there from someone I forgot to tell I changed my address. I keep an eye on my Gmail to find out when there are hot singles in my area or that there's a new sure fire diet pill that sheds fat instantly.