I have the lowest priced account on this, and I probably don't use it all that much, but it's useful (especially when you're in support) as a kind of insurance

I have the lowest priced account on this, and I probably don't use it all that much, but it's useful (especially when you're in support) as a kind of insurance policy for those times when someone goes, "One of these has stopped working - fix it", and your first thought is to reply, "What the hell is one of those?", and your second thought is, "I'd better find a book on whatever the hell one of those is."