I had five air entries into Thailand from May 1 to July 31. Every time I got a 30 day stamp on arrival. On my last entry, the passport control officer took a little too long scrutinizing my passport. I started strongly leaning towards getting a multiple entry six month tourist visa. But, on my way out of Thailand to spend a month back in the USA, I spoke to two different immigration officers at BKK and asked them if it would be best to get a visa for my next arrival at the end of August. Both were emphatic that as long as my entries are via air, and I stay less than 30 days per entry, I don't need to worry. Wondering if anyone else has had any experience with having a bunch of visa-free entries in a relatively short period of time and if there's ever been any problems. I might have just spoken to two incredibly lenient officials on my way out.
TLDR : Answer Summary
The original poster (O/P) shares their experience of making five air entries into Thailand within a few months, each receiving a 30-day stamp. They express concern after a passport control officer scrutinized their passport and consider applying for a multiple-entry six-month tourist visa. Two immigration officers advised them that as long as they enter by air and stay under 30 days, they shouldn't worry. However, comments from others caution that repeated entries could raise flags with immigration and suggest that a visa might be a safer option in the long run. Several commenters share their own experiences and insights regarding visa limits and the potential risks related to visa-exempt entries.