What is the best visa option for a 6-month to 1-year stay in Thailand?

@Matt ********

Twice per calendar year is the general rule but as many say on here it's at the discretion of the Immigration officer if you attempt a 3rd time within a year and in most cases you will probably get in ok..

If you are concerned then get a cheap flight to Cambodia or another neighboring country and stay there for a few days and then fly back in and get another 60 days..

Flying in and out seems safer than doing a day run over a border and back again..

The bottom line is this...

If the immigration officer dealing with you on the day you enter Thailand from anywhere (land, air or sea) thinks you are abusing the tourist visa exemption system and living in Thailand and not a genuine tourist then you can be refused entry after more than 2 entries in a year.

But in reality this is unlikely but it's always a risk..

@Dennis ******

yes. Twice. However it depends on the immigration officer for a third time. I know people who’ve done border runs for years. So don’t count on more than twice.