I always keep some cash ready to buy these dips. Got in sub 120. The lag prevented by 150s from going through.
problem: current 'crash' was so pathetic we only touched the price of about 2 weeks ago. I doubt it's worth it keeping cash just to buy in at a dip. Chances are the dip ends up being higher in price than the time you could have bought when your cash first arrived. There's not enough dips to do this I think... (unless you're lucky and a dip occurs when your money happened to arrive)
Unless you have an nearly unlimited supply of fiat... Or try to daytrade, selling high, but I consider this too risky.