Need help--71 vapor canister location

[GTCS]

Newbie question - Summit Racing sells what is probably a generic canister.
http://www.summitracing.com/parts/sm...olet/year/1973

If my '72 Cheyene already has a canister is it usable forever or do they wear out or get plugged. Someone cut off the hoses and I have a gas smell in the cab so I want to get the vapor system back up and running. I don't want to waste money but if they do get less efficient over time I'm OK with a generic one to use as a driver, while storing the old one. Are they all pretty much the same?

What are your thoughts?

Thanks