Can I enter Thailand on a 45-day visa exemption and later transition to a long-term retirement visa?

The original poster is inquiring about entering Thailand from Australia on a 45-day visa exemption and whether they can transition to a long-term retirement visa while in the country. Several comments provide guidance that it's possible to enter on a 45-day or a 60-day tourist visa (both extendable) and then apply for a Non-O retirement visa from within Thailand, given that the necessary financial requirements are met. It's advised to consider assistance from immigration volunteers or agencies, especially for navigating bureaucratic processes but there are mixed opinions on whether to use an agent or do it independently.