In reality, you gamble. In theory, you buy and sell based on the delta. At the beginning the delta of your put is small, perhaps 0.5 (really, it should be -0.5, but let's omit the negative sign!). So, to fully hedge your position, you need to buy 2 contracts of put for every 100 stocks you own. As the stock price lowers, your put options gain value and the delta also starts to grow. When your put options are deep in the money, their delta will be very close to 1, at which point, you will be over hedging your position. So you should start selling half of your put options. Conversely, when the stock price raises again, you will need to buy more put options to stay fully hedged. But you probably would like to just close the positions and walk away.