"Every other" is a useful phrase when talking about frequency which implies the following pattern:
x / o / x / o / x / o / x / o ..... etc.

In contrast, just "Every" is used when talking about the following pattern:
x / x / x / x / x / x / x / x ... etc.

"Every other" can be used to speak about frequency of how often you do something, such as:
  • Every other Saturday Tom plays golf with his friends

  • Every other year Cindy travels to Russia to visit her family

In the first example, Tom plays golf one sunday, then the next sunday he does not, and the next sunday he plays again. Tom plays golf twice a month, every other Saturday.

In the second example, Cindy travels to Russia one year, then the next year she does not, and the following year she travels again. Both of the examples follow the pattern: x / o / x / o / x / o / x / o .....

Other examples of how "every other" can be used are:
  • Every other person waiting in line will receive a free donut.

  • Every other customer who walks in the front door seems to have a complaint!

  • Every other microchip is pulled from the assembly line and inspected for quality.

"Every other" is an extremely useful expression to use when it is needed. It allows for greater accuracy in your expressions, and greater accuracy allows better communication.