毎年 - まいねん vs まいとし

[phreadom]

I've been seeing this both ways, and I'm wondering what the difference is, if any?

Is this purely a subjective style choice? Is there a slight nuance difference depending on which you use? Is it a regional thing?

I've seen a lot of things saying that both are in common use, but I've also seen people say that they've been corrected not to use まいねん by a native... so it seems like there is at least some difference in accepted usage depending on who you ask.

[shin1ro]

Hi, I'm native Japanese.
I hope I'm not rude to reply to this rather old post...

I believe まいねん and まいとし is exactly the same in their meanings.

To my personal impression, まいとし is used more frequently.
But I strongly believe its incorrect (just less frequent) to use まいねん.
In my impression, まいねん is used sometimes in formal situations but I still think まいとし is used more both casual and formal situations.

There may be a tendency of the frequency depending on where to be spoken,
but even so, I don't think まいねん is a regional word.

-shin1ro