Can someone remind me about Rentry Permits

My 1 year class O non imm retirement visa will expire late December. I think Reentry Permits will be the way to go this year.

Are these for me?

I will want multiple.

Will they be good for a year from the expiration date of my current visa?

Do I get these at Suan Phlu before departure in earl December?

Would you recommend I get them on arrival late January at Suwannaphoum airport?

Any advice, pitfalls to watch out for would bwe appreciated.