Is Steam email verification a thing?

Not regular but it is a thing, you usually only see it right after creating the account, maybe you just forgot about it, I've only seen it twice on my account.

Yes, happens sometimes. A message is displayed in the upper part of your steam account and then you have to verify your account through e-mail.

Im getting it approx. 1 time by year. You just click the send email and verify you still own it.

I'm surprised you've only had it happen once so far. I've gotten it about 6 or 7 times in the last 2 years.

You had me concerned for a while talking about the email you registered with. That's not what they are verifying - they are verifying that the email you currently have listed as your email is still in your control. They do this more often if you have acted in ways they consider... worth looking into. Exactly what that is is a mystery of course.

I think I have only had to do this once if at all in the 13 years I've used Steam.My login name is actually the email I signed up with, and that one has long since left my control, but that's okay - I keep the contact email updated.

Yeah, i get this way too often and it's annoying

It happens at times, part of their actions to make sure people keep their information up to date.
(To avoid cases where someone loses their login and then finds out it had an e-mail adress associated with the account that they haven't used in years)