How much is needed by age bracket to retire comfortably in Thailand?

Age 50-55 = $XXXk?

60-65 = $XXXk?

I ask because there was a post recently (another group) where a 52yo woman was planning to retire in Thailand with GBP 200k savings and GBP 1600/mth income.

To me that seems too small for retirement considering she may need that amount to survive another 30+ years.

What do you think, is that enough? Or much more needed?

(I'm thinking a minimum of $1000/mth is needed for a satisfactory, stress-free living)