At age 50 you can apply for a retirement visa. Consult a visa agent as soon as you land in Thailand to get everything set up before your birthday. I was able to switch from a visa waiver to the retirement visa without even leaving the country.
Australians: You guys get paid when you're out of the country?
The moment our passport pings at an Immigration exit point, all government payments stop until we ping back into the country again.
It is possible to get permission to go overseas for two weeks on some pensions and payments won't be interrupted, but in general government benefits are only for people who are onshore in the country. Sigh.