Theta measures an option’s sensitivity to time assuming implied volatility, price movement & interest rate are held constant. For example, if the value of an option is 10.00 and the option has a theta of -.20. After one day, the option’s value will be 9.80, 2 days 9.60. etc. Negative theta is obtained when the options position is long. Having negative theta is not a fun feeling if the price doesn't cooperate. As time goes by, the extrinsic value of our options will dissipate, which means we have to be directionally right before the expiration date in order to see a profit. If we have positive theta, time works in our favor. To obtain positive theta, we sell options. In the above example, we sold options for $10 and two days later we can buy them back for $9.60. If we are willing to buy shares of stock but at a lower price, rather than just sit and wait, we sell put at the desirable strike and hope the put will be assigned. In return for the obligation to buy the underlying