We're down only 12% from an all time high. It's only been a couple of days since the market reacted to Coronavirus. It's possible that if you buy now, you'll soon lose another 20% or more. At the same time, trying to time the bottom is a gamble. Dollar cost averaging might be the best & simplest choice for a conservative investor.

(disclaimer: I have $280 SPY puts expiring in April, and tomorrow is probably gonna be a great day, personally)