I just want to confirm what is possible. I live in the United States and I am a United States citizen. Have been to Thailand about 12 times over the past 10 years and always go r less than 30 days and take a trip to another country while I'm in Thailand such as Singapore, Malaysia ,etc. Does my times still start over regarding the 30 days if I take a trip in the middle of my stay in Thailand. For example, let's say I come for two weeks to Thailand and then take a five day trip to Singapore. Does my 30 days start over again once I enter back into THAILAND? At this point I'm not interested in anything extremely long term in Thailand. Maybe just extending from the 30 days to 45 or so by leaving the country in the middle of my trip to Thailand. Thanks for the information.

You will get a new 30 day entry every time you enter the country. Since you are from the states you will also get 30 days at a border crossing (G7 country rule).

You can also extend your 30 day entry for 30 days at an immigration office for a fee of 1900 baht.