Depends on how long I am staying, short time visa exempt, longer tourist visa and yes I have extended both at different times, but never back to back. I am married to a Thai and can stay longer, or based on being over 50. But I still work and love coming and spending my time in Thailand.
I'm an Australian and have entered Thailand from 2 times a year to 4 times a year for more than 35 years, I have never been asked proof of funds, onward travel etc,. If you are entering the Kingdom on the correct visa there will never be a problem.
If you have the time to spare you can get all Thai visas from Canberra Embassy by post, just need certified copies of Bank account, all forms and requirments are on the website