Do I need to leave Thailand to activate my NON-O visa after entering visa-free?

Greg Low . keep in mind: when you enter Thailand and activate the 90 days stay permit, the 1-year extension of stay will start and expire exactly 90 days after the date when you entered. If for example you exit Thailand now, and re-enter to activate the visa tomorrow on December 16th, you will get stamped in for 90 days, and the 1-year extension of stay based on retirement will start on March 13th. This date will remain the date when your annual "1-year EOS" will expire and needs to be applied for up from 30 days earlier. In case are sure that you will always be inside Thailand every year until this date and apply up from 30 days before this date, you are fine. If you wait until your 60 days stay permit expires, you are shifting this date further away from March 2026 and thus for every future year

What I meant to say:

For my own convenience, I regularly hibernate in Thailand since 18 years, from end September/beginning of October, to mid-March.

Placing my annual Extension of Stay Permit expiry date on January 4th, which means into the absolute middle-term of my stay, has advantages:

I do my 90-days report on the same day I apply for my next extension of stay.

And before my next 90-days report becomes due, I have already flown back to Europe. Easy peasy.