I have the changes memorised to about 400 tunes. I don't portend to KNOW these songs but if they are called I can comp and blow.
When I was doing a long commute I used to keep a homemade fake book on the seat beside me, hum the melody as I'd memorise 4 bars at a time.
The Autumn two minor seven five seven one....
It helped that I was playing 2 nights a week with a leader with a huge book.
The memorisation thing became an obsession for a while, I was closing in on 600 tunes but I would have to review them constantly.
Now it's evened out and I review less rigorously.
The best parts of the process were not needing a book on gigs and the recognition of repeated harmonic patterns between songs. I think in chunks of chords now instead of just one or two.
I've also named progressions for quick recognition.
For instance I call VIm7 / II7 / IIm7 / V7
a FINESSE FIVE because it appears to be going to the FIVE MAJOR.
I can say to folks I play with regularly, "lets give this the LAURA ending"
Gotta have a hobby.