<prompt> Human: About six months ago I decided to move 70k in savings from cash to stocks Vanguard SP 500 index fund. I decided to do this at a rate of 5k a month to mitigate the risk of a big market drop happening right after I moved the money. This is long term savings so missing out on a years returns for some of the money isnt the worst thing in the world.With the SP 500 PE ratio at over 19 I am beginning to worry that the market is becoming overpriced with lower expected returns or a drop happening soon. Ive read other commentary that this might be true as well.Now Im not proposing pulling money out. But is there any better strategy I could have other than continuing to invest in the stock market? Could I move less money per month into the fund, for instance, planning to buy later ifwhen the market is cheaper?It is tempting, but when I have thought it through it mostly seems like I am considering being a market timing idiot to add to prior idiocies like holding 70k in cash!Anyway the advice I see on rpersonalfinance is always inspiring and thought provoking so I am hoping you have some thoughts to help me understand my situation and make a smart decision.Assistant: When do you need this money? If its soon and youre getting cold feet, yes pull it out. If you need it in a few years move it to something less risky like corporatemuni bonds. If its not for a long time stop micromanaging it! Close the browser window. Check your statements quarterly just to see how things are going. All the historical data suggest that just leaving it alone through thick and thin is the best and only repeatable winning strategy.Risky investing is not for everyone. Its easy to celebrate big returns in good markets like we have now but if you cant sleep at night over your risk situation you need to be more conservative. Sleeping well when you understand how your portfolio works is most important.Human: Thanks for the advice. Im not considering pulling any money out of the market. The only question is whether and how fast I put money in to the market. So some management is needed unless you think I should just leave it in savings as it is now.  <response>: Youre talking about dollar-cost averaging versus lump sum. For a completely rational investor, lump sum investing will always produce a higher expected return, because it immediately moves your funds from asset classes with lower expected returns to ones with higher expected returns. Note that higher expected returns do not guarantee that your actual returns will be higher. According to an investopedia article, 6 studies indicate that lump sum investing has produced higher returns 66 of the time. 