I have a 1.5 story home,
http://www.dongardner.com/plan_details.aspx?pid=163

that has original paint from 2000. I'm pretty sure it's ready for
another as the caulking is cracking and the coverage looks thin.

I live in a somewhat humid area -- NE KS.

What would be the best time of the year to paint? What weather
conditions?

What would be the best paint? I hope this lasts another 10 minimum.

Should I hire a pro? How do I select?

Should I do it myself --- seems like a 4" brush is my most likely
choice.

Do I recaulk over the old caulk/paint? Or dig it all out and start
new?

What sort of prep should I do?

Feel free to direct me to links, etc

Thanks in advance,