Prior to '97, I had my record inventory under control. In that year, however, I joined the BMG record club and I started working for Borders, where they give employees promo copies of new CDs.
There were a couple of times when I accidentally took home a promo of a CD I already had a promo of.
I no longer work for Borders, and I haven't ordered a CD from BMG in a year. But the damage is done. I could go another five years without buying another CD, just opening the ones I already have. That's too many CDs!