Back in 1980, I was wowed by "London Calling" and announced my intention to buy the Clash album of the same name. My older brother talked me out of it by explaining the "Two Song Rule."  There were two parts to his advice:

1. Don't buy an album until you've heard at least two songs from it.
2. Don't go to a concert until you've heard at least two songs by the act.

Being young and influenced by his musical tastes, I didn't question his advice. To a certain extent, it makes sense. Especially when you have limited funds to spend on CDs (at the time it was records) or concerts, don't risk wasting your money on a band who only have one good single in them, especially if it isn't representative of the rest of their work. These days, that means getting the latest Now Top 10 hits compilation may produce more reliable listening pleasure than buying a whole CD by a one-hit-wonder-to-be.

But I've broken that rule plenty of times since then, with quite good results. I saw the House of Love just on the strength of "I Don't Know Why I Love You." They were amazing, although I felt conspicuous about staring at the band when people working at the show outnumbered the punters;  I guess most people who had heard the song were following their own Two Song Rule.  I worshipped the Wedding Present the first time I saw them, enticed by the recommendation of some British guy waiting in line for Godfathers tickets at a show in D.C. I've bought wonderful CDs and seen great performances just based on the guidance of friends or musicians I've interviewed. Through such advocacy, I discovered Crazyhead (I was their biggest fan in Philly by default), the Poster Children, the Walker Brothers and the Woggles.

It helps that I'm more willing to do my research these days. Back in high school, my only source of music information was the songs I heard on the radio. My friends all listened to the same stations, so I wasn't going to hear about anything else from them. We certainly didn't all agree, and I had to endure arguments that Journey actually had a shred of talent and that Madness inherently sucked just because they dared write a song, "Our House," with the same title as one by Crosby, Stills & Nash. But once I reached college, I started listening to non-commercial radio stations, which not only played music I hadn't heard elsewhere, but each station has a unique identity.  (WKDU played far more industrial music than WPRB ever touched, for instance.)  I started reading album reviews.  I started meeting people who hadn't listened to the exact same things as me, and could convincingly tout bands I'd never heard of. It encouraged riskier musical exploration. On the concert front, it helped that I developing interests in smaller bands; it's easier to take a gamble on a club show for $8 than a $30 ticket in a shed for the latest MTV sensation.

So my point? But an informed music consumer and make your purchases wisely, but don't be afraid to try something new. And I did finally buy London Calling seven or eight years later and wished I'd bought it sooner.