- Edited
I agree with pianoloverus. I hate memorizing sheet music, and the only practical reason to do so is if a piano randomly appears and I am without my documents.
Here's a nice article that makes the point that I'm too lazy to make myself.
The growing taste for watching soloists play from memory has actually narrowed the breadth of the repertoire. Vladimir Horowitz, for example, played a huge number of works at home from the score, but only performed a small repertoire from memory in public. Today many soloists won't commit themselves to more than a handful of works each season, no doubt partly because of the burden of memorisation. In the past few years, I've successfully memorised several solo recital programmes, each lasting about two hours. Had I allowed myself to use music, I could have performed the programmes much earlier, and with equal interpretative power. It was the sheer effort of memorising that added months to the process.