Do I need to report every 90 days with a one-year multiple entry Non-O marriage visa for Thailand?

As said, the visa is valid for one year, you can leave and come back into Thailand during that year and get 90 days admitted to stay on each entry. If you do not like to to border runs to activate a new 90 day period you can 60 days after any entry apply at Immigration office for the 1 year Extension of Stay. For this you need the financial requirement of 400.000 Thb on your Thai bank account 2 month prior the application date, or certified monthly income by your Embassy of minimum 40.000 Thb, or if income is inside Thailand 3 months tax payments over this salary. Next to this copies passport, marriage papers, wife papers, map, pictures. This Extension will be stamped as 30 days under consideration, some places do house visits and interviews during these 30 days, than you go back and get the remaining 11 months in your passport. If you like to travel during this Extension of Stay you need to buy the re-entry permit.

Check your entry stamp, you need to leave after 90 days.

When this one is near the end I believe you can apply for the yearly extension and you do a 90 day report rather than leave. I'm not 100% sure on that so I'm sure one of the mods will confirm or correct me there