I already wrote about that you should think about paying for your email service (or host it yourself if you’re crazy), but another important aspect is the email address itself.
Many people (and I also did this in the past) use an email address given by their provider like an address with @gmail.com, @outlook.com or any other. Using such an address is free of course, but it is definitely some kind of lock-in. Where do you use this email address? Do you keep track of all the places?
I don’t and I also don’t want to bother so many people remembering a new address when I switch providers. And because I often can’t remember any place I used an email to register, I also fear that I may lose access to some accounts, when I can’t use it to reset passwords. Due to this I keep all past email addresses, which prevents me from deleting a few mail accounts like my Gmail account.
But I now own the domain(s) for my emails. A domain isn’t that expensive, you can even get a simple domain for as few as 1€ per year and it’s really something worth spending that money on. But don’t get to obsessed with it and buy too many like I do all the time. 😅
Using your own email domain gives you not only the flexibility to switch providers as often as you want (embrace switching when you don’t like that service anymore), but also gives you the option to setup a catch-all mailbox, so that you receive all mails send to any address of your domain.
This way you can use a different address for every service you sign up (firstname.lastname@example.org). That is not only helpful when one of these lands on a spamlist, but also helps when a service leaks a email-passwords list. Hackers will have it a bit harder to try the same credentials at another service. (Although you should use different passwords for every single service!)