What, you may ask, does that have to do with musicianship? With playing a band instrument? Well, the first one is obvious: someone with a broken neck, or even just a broken arm, ain't gonna play their instrument too well. Even someone who just turns and sprains their ankle is gonna be crankier than usual, and therefore not play as well. And (2) has a LOT to do with musicianship, especially in a band where more members are over 50 than under, where most people are working at least one full time job all day before coming to band rehearsal, which is to say, we all need a bit of exosomatic memory. When the conductor says let's make that line a crescendo and then a decrescendo - write it in! When we announce that next week's rehearsal is in a different location - write it down! When you miss an accidental - circle it! When someone announces a web site for some musical cause, write it down! It's a lot easier to write stuff down compulsively than it is to grow new neurons to remember more stuff without writing it down!
Exosomatic memory: that's squirrel_magnet's term for PDAs, address books, or even just pencil and paper. For those of you who don't recognize the word, the roots are soma, meaning body, and exo, meaning outside. That is, memory that occurs outside of the inside of your skull.