I'm been here on multiple-B for some years now.

Today I went to immirgation for my new status.

I got my 1-year extension of stay based on marriage today (non -B )

When shall I apply for the next extension?

My stamp says October 13th 2009.

Shall I go at least 21 days before the expire date?

Do they have to send my papers again to immigration bureau in Bangkok?

edit reason: ( non-B ) is better than (non-

Edited October 10, 200817 yr by PoorSucker

When shall I apply for the next extension?

My stamp says October 13th 2009.

Shall I go at least 21 days before the expire date?

Do they have to send my papers again to immigration bureau in Bangkok?

Between one month before and the last day if you are brave.

Yes, they have to send your papers away for approval every year.