Some options may have contracts in every month of the year, but this is usually reserved for highly liquid underlying securities, such as ETFs on the S&P 500. Options such as these are often used to hedge a portfolio and, because they represent a basket of stocks, the security is more stable. The strike prices tend to hold up better as a result.
With single stock options, a given strike price that once seemed valuable can quickly become obsolete, such as a $25 strike price in a call option on a stock that drops suddenly from $27 to $15 over the course of a month.
LEAPS are not subject to standard expiration cycles because they are derivative contracts that are one year or more away from expiration.