What is the process for doing a visa run in Thailand after long-term stays?

Admin - please feel free to ignore this if you think it’s not informative.

Hi all. I’m American, just did a visa run after being in Thailand for 9 months on STV + one Covid extension. Here’s my visa experience flying from BKK to Hanoi & back, if it’s any help to others:

1 - My airline - Vietnam Airlines - did not ask about a ticket out of Thailand during the visa period. (Although I bought one, after reading posts on here.)

2 - At immigration in BKK, the officer asked me if I have a visa. I replied that I thought American citizens can enter visa-free for 45 days. She said yes, but how long do I plan to stay in Thailand - obviously she saw I’ve been here for almost a year. So I showed her my exit ticket & she stamped me right in. (My actual plan is to apply for retirement extension, but I didn’t have to go into all that at that time.)

3 - Re the exit ticket out of Thailand - this won’t work for everyone, but I bought an airline ticket using frequent flyer miles to a destination that I will definitely go to at some point. So only had to lay out $20 USD. Yes, now I need to change that ticket & there will be a fee involved, but it will get used sometime in the future.