I have a very poor memory. When I was a child I found spelling to be very difficult (I still do). In order to spell a few problematic words I had to figure out rhythmic patterns, which I still remember.
FI-FI-ELD (Mrs. Fifield, my second grade teacher)
CO-CH-IT-UA-TE (the name of the street where I lived)
Using musical tools to remember non musical things (and rhythmic patterns are musical tools) is really helpful, particularly for the musically inclined, but I have always had a problem with using non-musical tools to remember things musical. The only thing that has ever worked for me (and this is not advice because I have a very poor musical memory) has been purely kinesthetic memory, sometimes called "muscle memory," and, to a lesser extent, visual memory.
My weaknesses with musical memory used to be a problem for me, but now that I understand my strengths, I don't fret about it. Here's why:
1. Every musical experience is a new one for me. I cannot replicate the "way" I play a phrase intentionally, nor would I want to. Each subsequent movement of a Bach Suite or a Sonata or Partitia is a new treat, even though I have gone through the cycle of playing one a day (I'm a violist, so I can play both sets) for years.
2. Because I'm not relying on memory when playing with other people, I can allow my mind to expand and hear more of a whole musical picture. With every individual musical experience I have, the whole can sound completely different. And it often does (thank goodness).
3. Now that I am a fully-fledged adult, I never find myself in a position where I must play without music in front of me, unless, of course, I'm improvising or playing by ear.
I can recall only a couple of times when I was called upon to play from memory. Julius Baker had us memorize his set of warm-up pieces: Bach Allegro from the C-major Sonata, the flute solo from A Midsummer Night's Dream, the flute solo from Carnival of the Animals, and some scale patterns from Taffanel and Gaubert. Memorizing those passages meant that I could play them any time without thinking about much of anything. I learned those things kinesthetically and mindlessly, and could still, if handed a flute, play them kinesthetically and mindlessly (though my muscles would probably hurt a bit afterwards).
I have since learned that context is everything. Understanding the context of something is far better than being able to do the thing independently of its context. I am very good, for example, at playing scales and arpeggios in every key on the violin and the viola because I practice them in every key. But when I am confronted with a scale, arpeggio, or double-stop passage in a piece of music, that passage has an entirely different meaning and purpose than it had in my Flesch, Sevick, or Dounis books. I have to practice it in its own context in order for it to "work."
I have come to the realization that practicing scales, arpeggios, and double stops by themselves is great for building strength and to a certain extent for improving intonation, but in a harmonic context that is different from the one set up in the scale book (where you "live" in a key for a while, or you modulate to it from an expected harmonic place), a scale or an arpeggio or a series of double stops can be an entirely new experience. Also, in order to keep music interesting for all involved, I believe that everything should feel like an entirely new experience (even if it isn't really). Sometimes that can really mess you up when you have to "produce" in a high-pressure situation while playing from memory.
In 1980 I participated in an international flute competition in Budapest. Everything had to be memorized, so, for the first time in my life I had to perform from memory. I was young and ambitious, and I prepared as well as possible. It was a wonderful experience to be in a new country, eat new food, hear an odd language, and meet new people. I happened to meet a harpsichordist who wanted to talk with me about new ways of thinking about Baroque music, as well as the ways of the West. From him I learned that some the Bach Flute Sonatas were really Italian in style (something they didn't teach us at Juilliard), and that there was a tradition of playing Italian music that was really nifty when "applied" to Bach. I also met an Italian flutist who played in what I could identify as truly Italian manner, and suddenly I found myself re-thinking everything I was doing with the E-major Sonata I was playing.
I'm not sure what it was that came out when it was my turn to play, but it clearly did not impress the judges as a well-thought-out performance. I didn't advance beyond the first round. Had I been playing from music, I probably would have had a chance to consider what I had learned by using visual cues, but since I was relying on rote memory (the only kind I knew), I didn't have ample time or brain space to "re-learn" something that ended up being a musical revelation to me. I still enjoy that revelation.
I applaud people who can play from memory and learn new things at the same time, and I am totally impressed with people (particularly pianists) who can play in such a way that they totally forget about the notes and even the instrument they are playing, and can still make each musical utterance a new experience. I have come to accept that I am not one of them, and will never be. I have also come to accept the fact that its just fine to contribute what I can to the world of music in the ways I can.