note that you can apply for a 1 year retirement visa at age 50 OUTSIDE Thailand the first time, and one time ONLY
Need to show the equivalent of 800,000 baht in the bank that has been there for 3 months
then after your visa expires ( 1 year) you can apply for a 1 year extension IN THAILAND.
need to show 800,000 baht in the bank for 3 months
Sept 1st laws changed that no longer can your wife if she is under 50 tag on to your extensions.
if she is under tough luck, if she is over needs to show her own money in the bank
as to your kids, they also can not tag on to your extenison or visa

You can also apply for a 1 year mutiply entry type O visa, in your home country, but that means you need to leave every 90 days. They do not issue this type o visa outside your own country and doubt they would give it to you twice.
the extension you do not need to leave at all ever.