As previously stated 2 months before and 3 months after. No getting around this as you have to show copies of your bank book. If you can afford to keep the money in your account this is definitely the easiest way. You have more hoops to jump through with the monthly income.
If your Drivers License is in English it is fairly easy. You will need
Drivers License from your country
Passport
Certificate of Residency
Medical Certificate
Photos you will need for Residency Certificate
Photo copies of all
Then go to Land and Transfer office and watch a one hour video and three test. Reaction Time, eye test and one more. Pay your money and wait for license to be printed
If you don’t mind spending the extra money, up to 30,000 THB then you should come in on a Tourist Visa and go to a Visa Agent. It will all be arranged for you. And yes their will be people that will reply to this post and say do it yourself for 1900 THB. The more you pay the easier it gets. After the first retirement visas for my wife and I we do it ourselves.
Why would you want to do this? Certainly it won’t satisfy immigration financial requirements for retirement visa. The Thai person can use your bank card if you give her your pin. That is the safest way.