That's the problem, you can never tell when it's a good time to invest or a bad time. You think people thought it was a good time to invest in March 2009, when the Dow was at 6500? Many people pulled all their money out, thinking the drop would continue. Those who bought were happy. There's an equally likely chance the market will go up 10% in the next year as down 10%. And, there's definitely no pattern to the market.
For the record, I invested every dollar I had but $100 into the market between March and May 2009, though it was not much (several thousand) as I was but a humble student. I also bought TSLA at $28 and SCTY at $12, and I still hold both of them.
