constants vs vars

[kumarsena]

just wondering, i have seen a lot of tutorials use constants instead of variables to define for example, image size or location.
just wondering, what are the benefits of using constants instead of variables?

thanks
kumar

[Glacai]

Just a precaution so you don't accidently change the value within your program.

[jatar_k]

I use them for values that need to be defined across the system.

Constant == something that always remains the same
Variable == something that changes

I use them more in some applications than others.

[kumarsena]

thanks guys