I don't think you need to worry there. It's only a problem if you enter too often within a short timeframe. After one and a half years your previous entries won't matter any more. Well, unless they caught you on overstay or you have some criminal record from back then.

@Richard *****

there are more. If you go to the e-Visa site and apply for a new one, after selecting the Non-Immigrant type they ask to choose a purpose from a long list where I have usually selected "To stay with Thai family residing in Thailand". But from now on I think I will take the "Retirement" but it doesn't make a big difference since both are 90 days single entry (before there was a one year multiple entry but seems like they discontinued that one)

@Richard *****

I'm still married to a Thai woman - so I can use the non-immigrant based on marriage. But now I'm also older than 50 and in three days (I hope) I will for the first time enter with a non-immigrant for retirement.

@Dylan-Jye **********

yes, they always stamp. They only add which category you were using when entering. Like non-o or exemption (ผ.60-ม.17)

@Russ *********

I think it's simply they want the people who stay for longer to get a visa - which is not free

Be careful with too many exemption stamp entries. I spend about 50-70% of the year in Thailand. Last year after the switch to 60 days I used it three times. The third time coming from Laos at the immigration in Mukdahan the officer was looking at my passport and checking his computer very long and it seemed considering whether to let me in or not. He finally gave his stamp but now I make a 90 day single entry visa every time even when staying less than 60 days.

Thanks for the question, very helpful as I'm in the same situation right now. Only I will be living with my GF and her family. Stayed with them for two and a half years already and I built the house last year. 50% abroad so I made a new visa every three months. I live there for free but no lease contract or anything else documented on paper. So I guess we write a letter describing the situation or fill a TM30 and bring her to the bank and immigration in case there are questions. Or is there better advice?