In a recent study by Fidelity, the accounts that did the best were ones in which the owners were either dead or unaware they had an account.
Dollar-cost averaging and letting small gains compound over time is undoubtedly a winning play. If you bought stocks at the absolute top of the market just before the Great Recession, you’d have a total return of 71% today and 118% if dividends were reinvested.
The best thing you can do for your portfolio is to find some stocks you like, buy some shares and add to them at regular intervals regardless of market action. Your are going to be wealthy as a result. This way, your nest egg is going to be significantly larger than if you try to time the market by trying to sell tops and buy lows. Or even getting scared whenever stocks fall.