I learned a lot of “wrong” technique during my school days (1965-1974). My first “teacher” was a clarinetist, my second was a trombonist and my high school teachers were a pianist and a guitarist. They virtually knew nothing about violin technique so I was never taught any. (If it was in tune it was ok). I quit in 1974 and restarted last year (2015) and then… I hired a teacher in October who was a violinist and we started working on my wrong (bad) technique. I’ve still got a way to go, but I am learning, and with a lot more zeal than when I was a kid.
Back then I practiced because I “had” to practice 30 minutes a day on violin and 30 minutes a day on saxophone. After practice I could go outside and play.
Now I practice because I want to practice, and practicing violin IS my playtime… from 45 minutes up to 2 hours per day.