For individuals holding a tourist visa, no bank account and seeking to apply for a retirement visa and one-year extension of stay, it may be beneficial to consult with
You can contact the immigration office in Chiang Mai for guidance on the extension requirements. Handling it personally might be more efficient than going through an agent. Start with opening a bank account when you arrive.
Noted, however the key consideration is the cumulative duration of stay in Thailand within a specified timeframe without a valid visa. It appears she's optimizing her visa exemption periods and is likely to attempt a third entry within a twelve-month window.
It doesn't matter, as long as the immigration officer you’re standing in front of means you're using short-term solutions for a long-term stay in Thailand. You'll be told to get a proper visa anyway, and it's quite strict now. People get pulled aside and questioned after they've maximized one visa exemption. If you've maximized two in a shorter period, you should be prepared to be denied on the third one. I personally wouldn't dare risk getting denied and would be careful about advise anyone to just go and try with this history without a visa or a safe entry service through an agent at the airport.
For individuals who have maximized two visa exemptions, applying for a visa prior to their next visit may be a prudent decision. The Non-O visa category as Graham suggests is particularly suitable for stays of 90 days, provided the applicant meets the requisite criteria, including being over 50 years of age and demonstrating a monthly income of 65,000 THB or possessing funds amounting to 800,000 THB.
D'après ce que je comprends, seul le propriétaire de ce groupe ouvre des comptes bancaires pour ses clients dans le cadre de demandes de résidence/visas de longue durée, et pas seulement en tant que service indépendant.