The requirement is minimum 2 months prior application only but some Immigration Officers will tell or ask you to keep the funds in your bank account during the 30 day under consideration period which you get first.
You have to go back to the same office on 1 Sep with your passport and this receipt to get the answer of your application.
Advice: Do not walk out the office if you do not understand what to do, just ask the officer who took all your documents after you ask him/her that you like to apply for a visa.
It seems you are from the US, so you apply using the on line system.
For the purpose of visit:
Retirement (pension age 50 or above with a state pension and wish stay inside Thailand for no longer than 90 days there is a insurance requirement of 40.000 Thb outdoor patient and 400.000 Thb indoor patient, which is what most travel insurance offer.
Once inside Thailand during the 90 days you got on entry you open a Thai Bank account, make a foreing deposit of 800.000 Thb, after 60 days but before the 90 days ends you apply for the 1 year Extension of Stay based on retirement and once stamped in your passport, you apply for the multiple Re-Entry Permit so you can travel all you want during that year.
With crazy thinking you could go the other way by visiting the Immigration Office, get the hand out with requirements and apply before 30 Aug for the 1 year Extension of Stay based on employment.
a few copies and application fee are cheaper than doing a border run.