Practical Game Design

Variables

Avoid specifying numbers, numeric ranges, or any fixed values that are likely to change many times during development. Use variables instead, names that will represent those values, whatever they are going to be. This is also an effective way of writing pieces of documentation where some details are not yet defined, and automatically answers typical questions such as "How many of these are we going to have?" or "How long is this going to last?" Putting a variable in your design lets everyone know that a certain value must be kept flexible and open to change.