Interesting topic, Scott.

I began formal musical training by the age of 8 and never had "play by ear" lessons. I learned to play by ear much later, by the age of 17/18, and all by myself. Later, I developed an interest for jazz/latin music, listened to a lot of records, and took some lessons (for a short time, unfortunately) with two jazz pianists.

My approach to learn songs is the following. Most of the songs that people expect that I play, are portuguese pop, portuguese popular, brazilian standards, latin, and some international [english/american pop, some country, mainly] and have a rather simple chord structure / melody. I normaly easily memorize the chord progression (no "complicated" chords are needed; minor, 7ths, 6ths are usually enough) and the main melody line, from hearing a record of the song (or 2/3 different versions). All I have in front of me when I play live, are the lyrics (no chord table or LeadSheet), except in the case of a more unusual progression that I tend to forget (in that case I write a note near the lyrics). The exceptions are jazz or jazzy tunes, Jobim tunes, etc, that require more refined chords. In these cases I always have a LeadSheet with chords. My audiences - in parties or clubs - generally prefer "easy tunes"; however when in a lounge venue I play mostly by LeadSheet w/ Chords.

Examples: Girl from Ipanema, One Note Samba, Tenderly (LeadSheet w/ Chords); I play a country medley - Blowin'in the Wind + Take Me Home, Country Roads - entirely by ear.

-- José.