I am a big advocate for as much personal control and ownership of our digital lives as possible. As such, I naturally believe that any and all email you use should be sent and received under your own personal domain that you control (with the exception of select circumstances). Obviously this can be taken a step further to hosting your own email, but that far exceeds most people's abilities including my own. In the post, I'll go into the why, how, and my own experiences.
Owning your email is like owning the doorstep to your digital life. You can change providers without having to inform everyone that you've moved. You're also more secure if your provider decides to do something that doesn't align with your values. When you own a domain, your email provider cannot take your email address away from you. For example, let's say you you own the example.com and have your email address set as email@example.com with a service like Gmail. Here's two scenarios with a custom domain and with Google's @gmail.com domain. One day, for some arbitrary reason Google decides to lock you out of your Google account and therefore you're locked out of your email. If you're using Gmail's domain as your email address (ex firstname.lastname@example.org), you're basically screwed in regards to accessing, sending, and receiving your email unless you're lucky enough to get a hold of someone at Google to hopefully get things sorted out and have access to your email given back to you. The second scenario is the same except instead of email@example.com, you have firstname.lastname@example.org because you're smart and you use your own domain with Gmail. Instead of potentially being locked out of your Gmail account forever, you simple update your domain's DNS records to point to another email provider and you're ready to send and receive emails again with minutes.
I'll share a personal scenario, albeit less dramatic. I recently switched from Protonmail to a Norwegian email provider called Runbox. I don't dislike Protonmail. In fact, their web experience is very well polished (albeit sometimes slow) and having E2EE email (between other Protonmail users) by default is excellent. However, I became somewhat annoyed that I was receiving advertisements popups when I'd login into the web interface, and a "Special Offer" button that never goes away, all while already being a paid subscriber to both their email service and VPN. Subjecting me to ads to try and upsell me to a more expensive subscription that I don't need nor want just rubs me the wrong way. Secondly, I was continually running into issues with the encryption and the lack of open standards (which with Protonmail seem to be at odds with each other). Using a local email client requires the Protonmail Bridge application be installed which only supports email. There is no calendar or contacts sync whatsoever. Thunderbird is the only supported email client for Linux, though it's possible to use the bridge with other clients, they can be frustrating to set up. But I digress.
I was easily able to switch from Protonmail to Runbox with minimal work, simply updating a few DNS records. If, for some reason, Runbox decided to lock me out of my account for any reason or just does something I don't like, I could once again easily move my email address email@example.com to another email provider. I liken it to having a phone number and porting it to a different carrier if you're not satisfied with the carrier you already have. I don't need to let everyone know I'm switching service providers, I just make the switch and no one knows a thing (and probably doesn't even care). As for Runbox, the service is fine. Their web interface leaves a lot to be desired, but it works fine the few times I've used it. And seeing as how I want to use my own email clients and tools, only having to use their web UI a few times to set things up means it's working quite will.
Another benefit is that you can also setup custom aliases for different purposes such as firstname.lastname@example.org. Or you enable a catch-all so that any address before @example.com makes it to your inbox, allowing you to make up email addresses on the fly. If, for example, the car rental company absolutely has to have my email address I'll give them something like email@example.com (where I'll often then be asked if I work for the company). If they proceed to send me spam I can just disable that alias.
Getting your own domain and connecting it to an email provider is easier than it sounds, but it does come at a cost. Obtaining your own domain is fairly cheap (around $10 a year for a .com TLD) and using a provider like Fastmail, Runbox, Mailfence, etc can run you about $30+ per year depending on what your needs are. You don't even need to have it point to a website (though you really should). Note: I recommend avoiding using a .xyz TLD.
Some caveats to using our own domain comes down to two things, at least for me. First, working for a company or client that recommends or requires using their work email service is obviously more beneficial because it compartmentalizes work emails from personal emails. Secondly, I'll still use a burner email address for certain things I'll only need to use once. Temp-Mail is great for this when I don't even want to provide a service an email address with my own domain.
I've been using own domain for email addresses for a little over 5 years and gradually shifted to using it primarily in 2019, when I closed my 12 year old Gmail account. Currently, I have a single Google account which was solely created for a Google Voice number (for junk) that I don't use for anything else. I also still have an active Protonmail email account which I plan on closing at some point in the future when I'm certain no one will try and contact me there. Other than this, all my email communication is conducted through a few domains that I personally own.
Thanks for reading. Feel free to send comments, questions, or recommendations to firstname.lastname@example.org.