Interesting replies as usual.
For me, this is not just an academic question but a pragmatic one.
I don't want to be restricted by the number of pieces I can play and I'm hoping
I can get my sight-reading skills to a level where I can play anything (more or less)
without worrying about forgetting pieces I already know.
However, I see a potential contradiction here:-
I theorise that the harder the piece is technically, then the more one would need, or rather,
want, to fall back to the sheet music to remind them of the music.
But these may be the pieces that someone who has reached a 'diploma' or concert-level
may want to memorise so as not to hampered by forgetting difficult parts, and, to be able to give the best performance they can.
Which is why I wonder if easier pieces can be played from sheet music quite easily by good players.
In other words, is it possible to 'forget' easier pieces, and just rely on playing them
from sheet music so one can concentrate on memorising harder pieces - this is the point that seems contradictary to me.
The easier pieces, may be easier to memorise because, by definition, they are easier, rather than needing the sheet music as a reminder.
But I admit that easy to play may not mean 'music that is easy to memorise'.
As a grade 5 'intermediate' (?) player who's come back to regular practise after a hiatus of a
few years, I'm going through various methods, studies and pieces for grade 6.
And I'm trying to get to a stage where I can sight-read easily for the whole fretboard.
I'm almost there with the 9th to 12th fret, but the 5th string is my weakness (unsurprisingly).
So with this goal in mind, I'm working through LOADS of pieces from all the resources I have
and I'm finding loads of (lesser known) pieces all over the Interweb via delcamp and some of the
members' sites that are helping towards this.
So, if I follow this approach, hopefully my reading skills will be vastly improved soon.
But pragmatically, I can't afford to 'memorise' every piece or study/etude I come across.
Memorising each piece you learn has been touted as 'essential' in some quarters but whilst I can see
that this would give you the optimum chance to play the piece to the best of your ability, I can't see
how this is practical IF you want to play a wide variety of music.
As an alternative, I'm hoping to memorise only the pieces I want to perform
(for grade exams or as my favourites to family/friends etc) and everything else will be part of the
set of 'sheet' music I have that I can get out whenever I want something else to play.
So is this approach not ideal? Am I restricting my chance of being the best player I can due to not
memorising every piece - study or otherwise?
Maybe, maybe not. But on the flip side, I hear how us CG players are notoriusly bad at sight-reading
that I wonder if one of the reasons is because many put the onus on memorising pieces because
that's the percieved way to get to know a piece and be able to perform it to the best of your ability.
I actually have only really learnt 2 pieces all the way through over the years - Adelita, which I still can play
and Bach's Bouree (from BWV 996 - the one the rocker's love to play!), but I have forgotten Bouree and
I'm finding that it's not a quick process trying to go back to the sheet music to re-learn it.
I'm hoping this is because my sight-reading was not perfect when I originally learned the piece.
But I'm wondering if this is the kind of 'confusion' that other players experience when they try to
remind themselves of a piece or relearn it.
So I guess my critical mass for pieces is 1!
But I agree that different factors can affect the number of pieces one can remember. As some have mentioned - practise and the pressure to perform are relevant among other things.
And it may be that it will vary depending on where you are in your path to your learning goal. Someone who has reached a performance/concert-level may have a different objective of how many pieces to learn/maintain than someone who is still climbing up that hill, so to speak (like me!) where there are so many pieces and studies that one can try and learn from.