As a drummer, I often get questions related to my craft. One that I often get is, “how do you remember all of the different drum parts for so many songs?” When you think about it, it seems like that might be a challenging task, but it’s really not any different than, let’s say, a cashier who remembers all of the different PLU codes for a long list of items, or a chef who remembers all of the ingredients and their ratios to a complete restaurant menu. It’s simply recall; your mind retrieving parts that were learned , or written previously. If I’m conscious of it, sometimes while I’m playing, I can tell that my mind is thinking about parts that are measures ahead of where I’m actually playing. In a way, preparing me for what’s ahead. Keep in mind that there is a certain amount of variance acceptable within the parts played. No different than the variance a chef would have in the amounts of his ingredients. A little more salt, a little less paprika, you get the picture. It’s not an exact science but the closer your recall is to the original, the more the value is of the integrity of the song.