You first have to accept this basic principal: NO ONE knows where stock will be going. Anyone here tells you he/she knows how stock market will react exactly, oh well, good luck with that.
Let's say you have 1000 shares of QQQ (for simplicity), if you sell your shares, you are at the risk of stock market continue to push higher (you have already seen people here selling QQQ at 480, 485, 490, 505). If you hold your shares, you are also at risk of big drawdown (such as early April)
Hedge with options allows you to hold that 1000 shares of QQQ, by paying a small premium. If market continues to rise, you still have your shares. If market goes down, you receive some level of protection (usually 60%-70%)
