Judging by your last post for advice here, it appears he's been here on border-bounces since March or April.
Generally, six months (give or take) appears to be the point at which people who've been using tourist visa-exemptions to stay long-term start to run into problems.
I used the word "always" when I should have used "long".
When I first got here in 2013, I'd run into people while on visa runs who were basically living here for years on end on tourist stays. Thai wife, off-the-cards teaching jobs in some village somewhere, the lot.
But then the 2014 coup happened, and they started enforcing things. The requirement to have proof of onward travel, accommodation, and 20,000 Baht (or equivalent) was already there on paper, but very rarely enforced.
After 2014, they started enforcing it, and demanding it from people they suspected of not being genuine tourists.
Obviously, this relaxed over Covid - but then after the pandemic ended, they cracked down again.
Its always been the case that immigration pulls aside & questions people they suspect of just living here on back-to-back tourist visas and/or border-bounce stamps.
Including Chiang Mai airport. I was pulled to the back office and questioned there in July last year when entering on a tourist visa. I had had just two border-bounce stamps that year, and previously had been on a Non-B for teaching for 4 years.
I was allowed in, but had to show them proofs of inward travel, finances etc.
Obviously some people are able to stay here for quite a while (over a year or so) on nothing but short-term tourist stays. Other people get questioned on their third or even second entry. But while the amount of time you can stay here per year on tourist visas is technically unlimited, entry has always been at the individual immigration officers discretion.
Probably "unlimited" in the same way that visa-exempt air entries already are "unlimited".
No legal limit, but after 4-8 months (give or take) on nothing but back-to-back border bounces, you have a *high* chance of being pulled out of line to the back office & questioned about what you're doing here.
If you have a visa, there is no land entry limit (though if you've already been here multiple months on short-term tourist stays, you run the risk of being questioned or even denied).
There is a legal limit of two *visa-exempt* land entries in a calendar year.
So to clarify; your 4 land entries:
1) Were they all visa-exempt?
2) Did you make them before or after Jan 1st 2024?