[Calgon]

If you create a stock function, it's a function which is only defined in your AMX when you use it somewhere, i.e. in a command. These are optimal for functions you're not sure if you'll use, and are a lot more minimal than public functions. Stocks can only be called in the script you're currently using and can't be used in timers.

If you create a public function, it can be called at any time. It will always exist in the AMX, unless you remove it when you compile again. Public functions can be called in timers, across different scripts, through plugins and various other ways. All public functions should be forwarded.