The long-term goal for all player/singer applications that don't REQUIRE reading is develop your ear to the point that "playing by ear" is incredibly accurate for you and supplies all the information you need to succeed with your songs. To effortlessly pick up subtleties and fundamentals through what you hear is an awesome blessing. To achieve this goal, though, I think you need to spend the first few years playing with music. A chart, words and chords, just the words on a sheet for vocalists. Don't be without that chart as you work on your music. People who aren't working with charts in the beginning, before they know a lot about music and chords and inversions and scales, tend to try and memorize everything and amass too many details to retain. If they're having any success at all with their music, this quickly becomes hundreds of songs to be memorized. Using a chart, which you amend and notate with the greatest of ease, allows you to customize and mark difficult sections immediately and quickly INTERNALIZE the musical issues you are facing. It seems to allow you to work more toward organic development of principles of musical excellence rather than slaving over the details for this exact piece. I think that's because you'll quickly see you're making the same notes over time and you gradually internalize these things. So, paradoxes of music - work with a chart to develop your ear. Go figure.
Keep your eyes on the page, not your hands. If you can play it, looking or not, you are 75% of the way towards not having to look at all.