I think it really depends on what stage you are with your playing. Most of us bassists/guitarists usually just took off with reading tabs.
Later, even after we memorized, or became familiar with the fretboard, we still can't read standard notations, but at least we know what notes/scales/time signature we're playing after knowing some music theory.
http://www.basslinepublishing.com/
The above link is about a long-time Mark King fan, Stuart Clayton. He was such a big fan that he started transcribing Level 42 basslines in standard notations when there were none available in the market.
The interesting comment from Mark King on his transcriptions is this: "
As I can't read music, I have no idea of what's going on, but it looks really great." (Extracted from Guitarist magazine April 2001 page 15)
Interesting? It's not uncommon that a lot of our guitarist/bassist heros couldn't read music.
B.B.King is another example. He didn't even know what's he was playing in his instructional videos. To him, the only thing that rules his great blues solos is: "It sounded good."
If you're someone who is "playing by ear", and if you're good at it, I don't see any need to force yourself to read standard notations. Techniques and speed development do not depend on reading music. You can still go on to develop your skills, to play complete songs, and to improve on your techniques.
But what Mr_KeyboardMan mentioned is true, if you're doing it for a living, e.g. you're a sessionist, you gotta know how to read music well. Because before the recording/rehersal starts, the first thing you receive is the scores on the songs you've never heard before. That's when you need to read music to deliver your playing.
I gave up on reading standard notations, but i'm still digging music theory, which is more important, for me.
My many cents :wink:
