I had good intentions of keeping a quilt journal, but after about 3 quilts, I forgot about it. Besides, it was too small. I should've had a full-size paper thing.
If I had to start again, I think I'd ask myself what I want to remember for each quilt, then create a template on the computer, print a couple copies, and experiment with actually using it as you quilt.
Start date and End date
Size
Fabrics (maybe create a grid for gluing small samples to) or selvedges with enough of the
fabric showing
Recipient
Occasion
Thread (if important)
Special stitches
Problems/challenges (What I'd do differently next time)
And pictures! Printed pictures.
I had a blog over a year ago and had kept better track that way than on paper. But I abandoned my blog (which I sometimes regret because I journaled not only quilting but everyday life and feelings).
So, I guess I wouldn't invest much money . You have to know yourself and what is the fantasy you vs. the real you. The real you will always win out in real life