Is leaving Thailand for 4 days enough to obtain a new 45-day entry stamp upon returning?

A US citizen with a 45-day entry stamp and a 30-day extension is considering flying to Vietnam for 4 days and returning to Thailand for another 45-day stamp. Community members suggest that leaving for 4 days could be sufficient, but it ultimately depends on the passport control officer's discretion. It's also recommended to have onward travel plans to avoid potential issues upon re-entry. Alternatively, some suggest it's possible to exit and re-enter Thailand by land, allowing for multiple visa-exempt entries within the calendar year.