If a person has no assessable income, there is no requirement to submit a tax return. I'm in that situation, although my position again is somewhat different. Although I'm in Thailand for more than 180 days, I am a certified Australian Tax Resident, and under the terms of the DTA, this takes precedence over Thai Tax Residency, and hence I am deemed solely an Australian Tax Resident, hence I am not required to submit a tax return. This has already been confirmed by Thailand Revenue Office. But again, I emphasise that every individual is different and there is no "one size fits all" process
ATM withdrawals and credit card expenditure are both potentially tax assessable as they are classified as "remittances". However, there is no hard and fast rule as every individual has a different financial situation and each country a different DTA
Actually he's essentially correct, although it's difficult to be totally precise because every person is in a different situation. However, the very basic rule is tax is only liable on assessable income