Paperless Sheet Music
After years of lugging around Real Books and building binders of lead sheets for Sidetrack I moved to digital music score readers. My first was iGigBook, but their technology stagnated and for the last few years I have been happily using forScore.
A digital score reader allows you to load and index a combination of digitized fake books (such as the Real Books) and individual pdfs of one-offs or original tunes and carry thousands of pages that are easily accessible on your iPad or other digital device. To make this work you need an iOS device (preferably an iPad or iPad Pro for readability), pdfs of fake books and/or single tunes, and an index that connects the titles (and optionally songwriters and styles) of the songs in the pdfs with the page.
Alec Katz has written and shared an excellent commentary on forScore on his website including links to many of the most commonly used indices.
I use a combination of forScore for reading/organizing lead sheets, and iReal Pro for "play along" chord progressions with audio. Because melodies are copyrighted, but chord progressions are not, iReal Pro can maintain a library of chords (but not melodies) and allows you to practice at variable tempos using "music minus one" for piano, bass, drums, and horn.