This image explains very well how the markets work, all of Bitcoin's gains this year have occurred in 9 days, good luck trying to time the market going in and out. Attached is an example from JPM: - According to a study by J.P. Morgan Asset Management using data from the S&P 500, if an investor stayed fully invested in the S&P 500 from 1999 to 2018, they would have had a 5.62% annualized return. However: If they missed just the 10 best trading days during that same period, their returns would dwindle to 2.01%. Missing the best 20 trading days during that period would have resulted in negative returns (-0.33%). If they missed the best 30 trading days, their returns would decline further to -1.97%. If they missed the best 40 trading days, they'd see an annualized return of -3.35%. Missing the best 50 trading days would result in an annualized return of -4.45%.