While everybody is wailing about P(ITM) and expectancy and all that, keep in mind that most most most people do not hold through expiration: they exit-or-roll when the price doubled from what they sold, or they exit-or-roll with their strike ATM-regardless-of-DTE, or they exit (triumphantly) when profit hits some percentage (but less than 100%max). Just to yardstick the price-doubling, the probability of that (colloquially known as P(HIT)) is roughly double that of P(ITM). Truly, "Shit happens" should cause some pause here......
Not sure I understand what you mean about "Shit happens". And definitely, I never hold anything till "max profit". Usually, take profit, move on.
There are only 2 parts to buying an option be it a call or put option. You place a "Buy to Open" order on a put or call depending on which you are trading, the number of contracts and the strike price. I use a limit order to make sure I do not pay more than I want to pay. Of course, most times, you pay the Asked Price. Just match your limit order price to the asked price. When you want to close your position, you "Sell to Close" your option whether you made or lost monies. Now, that trade is closed for good! If you bought your say call option for $300.00 and sold it for $800.00 then, you made a $500.00 profit.
Yes, shit happens. Let's say you are one of those that collect premium for a living. Just after Christmas, you saw CELG had an IV of >50% (higher than HV), stock at $61 and change, you figured collecting a rich $0.85 premium for a call that expired 1-18-19 with a strike of $70 was very safe, after all, it was DOTM. Today that call option is worth $18 with 2 days remaining from expiration. If you were naked and on margin, you would likely be wiped out. I pick CELG because someone created a thread on CELG around that time. https://www.elitetrader.com/et/threads/celg-on-sale.327472/ If you are a chart reader, you won't know the stock would gap up $25 in a few days.
There are 3 main strategies which are pullbacks, reversals and breakouts. I use those to get into trades. Take note there is no such thing as a sure thing. If a stock breaks out of a trading range, there is always a chance that the breakout fails and goes back into the trading range. In that case, the trade fails and counts as a loss. Close it out and look for another trade. My win rate is 40% which means I lose 60% of the time. You have to accept you are not going to win most of the trades. What matters is you do not risk more than 2% of your account in one trade.