What'* the average life span of these things? Do they ever get full or need to get replaced? What is their role?

Ideally, they never fail, except the solonoid (purge). On some years, the solonoid is individually replaceable, on others, it isn't.

When it gets fuel in it, it runs it back through the system, so it should never 'fill'. If the solonoid fails, you'll get a code and a light.

I was just curious, because I was running the car today and heard the solenoid on it clicking for the first time ever. Sounds like a plug wire arching.

It'* usually louder in the cold. Many of us have experienced this.

Well glad to know there'* nothing wrong.

what is this charcol canister for?

Traps fuel vapors to protect your environment, then purges them back into the TB when it has enough.

wow i didnt know that i bet their alot of weird of stuff i didint know cars can do.

How much before it usually purges?

This much >...................<