I leave country on Nov. 1st. I get my 3o day extension on 23rd Sept. So I can stay till Oct. 24th. and then do border run or fly some where.My question is if I go some where before the 24th of Oct. does that automatically erase my 30 day extension?So say I drive to Laos and then come back I just get a 15 day visa.I know pretty basic question but was just wondering what my options are.

You can buy a re-entry permit to keep your current permitted to stay alive for 1,000 baht from local immigration office prior to leaving. You enter that number as your visa when you return and get the same permitted to stay stamp you had prior to leaving.

If you do not than any extension of stay or visa entry is lost.