@Jo *********
I think you were lucky because you spent much more time in the country than is typical of a standard tourist. If you tried this again this year, you'd probably be denied entry.
What is key is to spend MORE time AWAY from Thailand than in, within a 6 month or 12 month period. You definitely want to spend say 14 days or less inside the country on each visit followed by several days or weeks away before your next entry. You can generally keep repeating a similar pattern like this, but 210 days out of 365 is pushing it. Less than 180 or even better, less than 90 and you should be sailing through immigration.
However, there is no hard and fast rule other than a loosely interpreted 180 in 365 days or 90 in 180 days rule that some officers use.