It may have changed since but about 10 years ago once an newly ordained monk received his monk papers he could get a 1 year visa and would be expected to report to immigration every 3 months to prove he was still a monk.
Before that it was much easier, but men had been ordaining to get a long visa then disrobing and continuing to use the visa, so monks who have been in Thailand longer than that probably have better conditions.
"Whenever we feel that we are definitely right, so much so that we refuse to open up to anything or anybody else, right there we are wrong. It becomes wrong view. When suffering arises, where does it arise from? The cause is wrong view, the fruit of that being suffering. If it was right view it wouldn't cause suffering." - Ajahn Chah
"Remember you dont meditate to get anything, but to get rid of things. We do it, not with desire, but with letting go. If you want anything, you wont find it." - Ajahn Chah