The last two years, I started each day with a handful of vitamin C (five or six grams) washed down with an Airborne. No other changes. Ate irregularly, drank to excess once or twice. No drugs to speak of, maybe a puff or two off a joint. Didn't get sick.
This year, I'm passing up Vegas entirely because my niece is getting married in Phoenix on Saturday. Extreme, but effective.
--t