A layer cake, jelly roll, or charm squares?

(For new quilters: a layer cake is a collection of 10" x 10" squares, jelly rolls are 2.5" x 44" strips, and charms are 5" x 5" squares.)

Mostly these come with about 40 pieces in each set. Is that a good number? Or would you like the option of being able to buy groups of 20 pieces too? (In case 40 is not enough, or too much.)

I've only used a jelly roll one time; it was okay but I wouldn't purchase one. I felt too limited by the color choice--some I would have liked more of, some I didn't use. I've never bought squares or or charms for this same reason.
I rarely buy less than a yard of fabric at a time. This is just me though, because precuts seem to be very popular. (I also fear cutting wrong and not having enough fabric.) I like coordinating my own colors (even if they're not great) rather than using someone else's choices.

I love charms, I think because I LOVE scrap quilts with LOTS of varity, and never have LOTS of money, lol. They are usually affordable!

I think a jelly roll is probably the most versatile, so I'm more likely to buy those than the other pre-cuts.

Sometimes I buy a jelly roll with a layer cake or some charm packs. With this combination, a lot of the cutting is done and you can go right to work, putting together the quilt.

For me - charm squares.

if i'm working on a charm quilt or a nickle quilt then 5" charms squares are the way to go...if i'm working on a strip quilt or bargello...strips are the answer; if i'm working on a big-block or scrappy then 10" squares may be do-able.
personally i seldom buy pre-cuts...i do not like to be limited by what i can do with my fabrics. i have received a few as gifts.
the outer blocks around the crazy center of this quilt bali jelly rolls were used.

I use charm squares, but I do want to start using Jelly Rolls. They are just more expensive.

If I don't have a project in mind I would buy a layer cake. I have a few projects "on the list" that use jelly rolls but otherwise I doubt I would purhase one.

I love jelly rolls and charm packs. Have a good supply-buy them on sale. Never used a layer cake but I did purchase sesveral when Connecting Threads had their sale before Christmas. Seems that they would be very useful since they are larger.

I have used all 3. Sometimes I don't want to have to think about putting colors together or have to cut it myself and the precuts are so handy. I'm not sure I would use packages of 20 though.