I have 10% cash on the side, will put in if S&P drops to 2280 but I have a 50 year horizon, so that wouldn't make/break me anyway.
However, I have my parents money they need to move out of a very bad investment, that will be DCA over the next year. I can't predict ups/downs and won't take the risk with their life savings but they also don't have the luxery to "wait" for a better time, so best to average it in and at least get them into them back into the market, can't do worse than what their advisor had them in... they lost 2% last year.... ummm rest of the world gained 15-20% they managed to lose money... I'm positive i can beat that.