Cannot be used. The Thai phone card only gives you a 30-day period for each recharge. Unless you recharge 12 times in Thailand or buy a year-long date, otherwise, the number will be recycled after two or three months.
There will be no impact if you don't log out. A friend comes to Thailand three or four times a year. Every time he returns home, he throws away his Thai phone card. Then he buys a new phone card every time he returns to Thailand. There is no problem.