Will I run into any problems renewing my Annual Retirement Visa & Re-entry permit 3 weeks before the current anniversary date?  I realize the next anniversary date may be moved up 3 weeks but I want to make sure there is no rule that you can only renew 2 weeks prior etc.  Thanks for your help kup!

Up to 30 days before. 45 at some imm offices

One month before is the general rule. They will date it from the previous expiry date. 

Your current "anniversary date" will not change. 

I asked this question at my local I/O (Phayao) and was told "up to 1 month before due date."   

Previously at the old Bangkok I/O (Suan Plu) I was allowed to make an extension more than 1 month in advance by submitting a letter requesting 'early extension, and giving a reason. (Business in home country.)  

I have no ide if this was official policy then or now.  Suan Plu were often more helpful than other I/O.

Up to 45 days before at some offices.

16 minutes ago, Robin said:

I asked this question at my local I/O (Phayao) and was told "up to 1 month before due date."   

Previously at the old Bangkok I/O (Suan Plu) I was allowed to make an extension more than 1 month in advance by submitting a letter requesting 'early extension, and giving a reason. (Business in home country.)  

I have no ide if this was official policy then or now.  Suan Plu were often more helpful than other I/O.

Bangkok, Chiang Watanna, allows up to 45 days prior without any special reason.