1. Enable roaming 2. Check balance, will tell you also end of validity 3. After minimum of 3 months of use you can extend the validity for up to 180 days just by sending some code (Google it! ) and pay about 15 THB for the service.
"The Burmese are wonderful people. " I did not say a single word about "The Burmese" in general..., was talking about the Burmese scumbags in uniform only too eager to steal your money... Big difference!
I see. As others have pointed out: lot of uncertainties, corrupt Burmese cunts eager to steal your money, besides supporting a government that brutally oppresses it's citizens... are the drawbacks.
Do yourself a favour an go to Vientiane instead ! "I’ve got a single entry in my passport unused." Yes, if it's within the validity timeframe you can use it.