Just got my multi entry non O Visa from Brisbane, so this means I can stay up to 90days in Thailand every time I enter the country?

Yes

You will get 90 days every entry.

Re-enter Thailand 1 day before the visa itself expires and you get another 90 days.

(You could even do it on the day itself, but better to be safe than sorry).

Summary: the last day of your visa you make one last more visa-run so you get 12 + 3 = 15 months

Summary: the last day of your visa you make one last more visa-run so you get 12 + 3 = 15 months

If doing a daily van run...if you take an out of country trip, be sure you return to Thailand on or before the expiry date of the visa.

Related to this, if one has a 1 year non-O visa and multiple re-entry permit, but one leaves the country for more than 90 days, say 100 days, what happens when one returns? (Assuming the 1 year visa has not run out).
Thanks.

Related to this, if one has a 1 year non-O visa and multiple re-entry permit, but one leaves the country for more than 90 days, say 100 days, what happens when one returns? (Assuming the 1 year visa has not run out).

Thanks.

I think you have an extension of stay not a visa. The only limit you have is being back before your extension runs out.

Edited October 3, 201312 yr by ubonjoe

Clarification;
I have a non resident retirement visa (Non IMM 0-A). As mentioned, I also have a multiple re-entry permit. So the question is what if I leave the country for more than the 90 days required for address update?
Thanks again.

You do not need to make 90 day reports unless you are in Thailand for more than 90 days. You make the first report 90 days from date you re-enter the country.