Today I was revising something very elementary on a stringed instrument: where to find a note an octave higher? On something like a bass, which typically has a consistent perfect fourth interval between each string, once you find the patterns, you can go on applying it along and across the neck.
In this case, and assuming you want to avoid big jumps, there are just two patterns: up two strings and two frets or up three strings and back three frets. I’m discounting other options, like up one string and seven frets, as requiring too much of a stretch on most instruments. On a four string bass, the +3/-3 pattern only gets a small amount of use in the range of a hand span or so but that increases as you throw more strings into the mix.
What I’m actually aiming to do is improve my ability to find any given note in any part of the neck by dead reckoning but patterns are a way in as I work towards that.