On the first renewal do I have to go back to Laos? Can I do it in BKK? Im a 30 day on 30 day off oil worker so cannot be without my passport for any time incase I'm called away.

First time went very smoothly thanks to lads on thaivisa. Also for instance if I come back and my visa has 7/10 days how long am I stamped in for.

Thanks.

Believe you are asking about a multi entry non immigrant O visa valid for one year? Savannakhet is the go to place for this type of visa on basis of marriage to a Thai.

Your 30 day rota does not really allow one year extensions of stay from immigration inside Thailand (which in any case would require extra re-entry permit to allow travel) - so the above visa is normal in your case.

If you wish to obtain a new Non O multi-entry visa on the basis of marriage this can only be done in Laos

If your visa is valid you will receive a 90 day permission to stay when returning.

Thanks lads that helps. Another trip to Mukdahan then.