I played 12 string guitar and a bit of Mandolin since the 60's. I can't read music but am a pretty adaptable rhythm player. Then in 2007 arthritis set in on my knuckles which made chords and hitting people painful (joking)
around that time our church band bass player moved south and we didn't have a replacement so as my wife also plays 12 string it was suggested that I learn bass. Knew nothing about them or how to play one so I bought a Mexican jazz, printed a bass neck diagram with all the notes marked and memorised it. I looked at some of the songs we do and it looked fairly easy......
It isn't!! I did quickly learn runs from one note to the next and I can accompany on a basic level without sounding too boring. Ann can read music so I just have the bass notes for songs written above the words I then add bits here and there to make it a bit more fluid and it works for the type of music that we do.
I'd like to be better but I understand bass, it's not instinctive when you've played guitar for so long, I can't easily 'jam along' so I get despondent and lazy and just do what's needed. I'd like to learn things like lucy in the sky with diamonds or we gotta get out of this place, but I'm not sure how to do it as I can't read music.
Plus I'm 66 so hardly ripe for a new career