After each option's expiration date, the option can no longer be traded. From a trader's perspective, expiring options will seamlessly disappear from the account, replaced by the corresponding stock position if the option expires in-the-money.

Now that you know the various outcomes for equity options at expiration, let's discuss the specific days that options expire.

Equity options have standard and non-standard expiration dates that are available to market participants. 

Standard options expiration occurs on the third Friday of each month. As a result, the last day to trade options in the standard monthly cycles is the third Friday of each month, which will be between the 15th and 21st day of the month. If the third Friday of the month falls on a market holiday, then the final day to trade the standard monthly options will be Thursday of that same week.

Any expiration date that isn't on the third Friday of the month is considered to be non-standard, which includes weekly and quarterly expiration cycles. Weekly expiration cycles typically expire every Friday, except during the weeks of quarterly expirations.

The following table summarizes the various expiration types you'll encounter when trading equity options:

As an options trader, you'll always be able to choose from expiration cycles of varying durations. The shortest-term expiration cycle will, of course, be 0 days (expiring that same day), while the longest-term expiration cycle will typically be approximately two years away.

As an example, here were all of the available expiration cycles for Apple Inc. (AAPL) options as of December 9th, 2016:

As you can see, there are 16 listed expiration cycles. You may notice that the weekly cycles are more present in the near-term, while the longer-term cycles are primarily monthlies. Longer-term expirations will typically consist of standard monthlies because weeklies aren't listed until a few weeks before their expiration dates.

Alright, so you know what an option's expiration date is, but how do you choose which one to trade in? In the next section, we'll discuss how you can go about choosing an options expiration cycle to trade.

With so many available expiration cycles, how do you decide which one to use? When choosing an expiration cycle to trade, there are two factors to consider:

1) The options strategy you plan on trading

2) The amount of trading activity in the expiration cycle you're considering (gauged by volume and open interest)

Let's run through each of these considerations one-by-one.

Most of the time, options expiration cycles with less than 100 days to expiration will be used because most options traders have short-term predictions for the stock price or implied volatility. 

Additionally, traders who primarily sell options may prefer staying in near-term expiration cycles because short premium strategies profit from time decay, which is virtually non-existent in longer-term options. 

Conversely, traders who primarily buy options may also prefer shorter-term expiration cycles because short-term option premiums are less expensive and more responsive to changes in the stock price.

Then who trades long-term options? Well, a common way to utilize longer-term expiration cycles is by purchasing deep-in-the-money calls or puts to replicate long or short stock positions. By purchasing long-term, deep-in-the-money calls or puts, traders can minimize losses from the decay of an option's extrinsic value while gaining exposure to shares of stock with a lower margin requirement (more leverage).

The second consideration, and perhaps the most important one, is the amount of trading activity in the expiration cycle. Trading activity can be gauged by option volume and open interest for a particular stock. You'll learn about volume and open interest in-depth in one of the following guides, but for now all you need to know is that more volume and open interest is a good thing. 

As mentioned previously, most traders prefer to trade short-term expiration cycles, which means the most option volume and open interest will be in the near-term cycles. Additionally, standard monthly expiration cycles will typically have far more volume and open interest than weekly cycles.

To validate this, we compared the open interest and volume in each of AAPL's expiration cycles from the table in the previous section. Here were the results:

In this case, the weekly cycle with 0 days to expiration (expiring that same day) had the most option volume, which makes sense because many traders adjust or close their positions on the day of expiration. Considering only standard options expirations, we can see that the first two monthly cycles have by far the most volume. 

So, what does it all mean? Well, trading the two nearest standard monthly expirations benefits traders in terms of entering and exiting positions fluidly. However, if your strategy is built for longer-term or weekly expiration cycles, then of course you'll have to use those.