I think learning more than one instrument adds depth to your appreciation and perception of Music.
I make a living as a session bassist but chose to play the acoustic guitar in my own band as a songwriter. Then I got a harmonica and added it. Two years back my girl friend gifted me a ukelele and I kept playing it while travelling. Now I can play some banjo, keys, mandolin, mandola too. I can only improvise on guitar and bass though. The rest I can only play enough to sound good in a pre determined context. But a lot of ideas cross over and help you innovate with your primary instrument. It also improved my overall understanding of Music.
One of the main reasons bassists must learn either guitar or piano is cause it is a good way to train the ear and understand harmony.
Cons?
It is expensive and time consuming to keep up.
I also feel a bassist can't benefit as much from being a multi instrumentalist in a live band since bass guitar is integral to the structure and rhythm. A guitarist may play keys or saxophone or guitar/harmonica or banjo/mandolin in the same set of a band on different songs. A bassist can't stop playing too long.
Oh and I was a drummer before I picked up the bass guitar after a basketball injury to my ankle ligament.
I make a living as a session bassist but chose to play the acoustic guitar in my own band as a songwriter. Then I got a harmonica and added it. Two years back my girl friend gifted me a ukelele and I kept playing it while travelling. Now I can play some banjo, keys, mandolin, mandola too. I can only improvise on guitar and bass though. The rest I can only play enough to sound good in a pre determined context. But a lot of ideas cross over and help you innovate with your primary instrument. It also improved my overall understanding of Music.
One of the main reasons bassists must learn either guitar or piano is cause it is a good way to train the ear and understand harmony.
Cons?
It is expensive and time consuming to keep up.
I also feel a bassist can't benefit as much from being a multi instrumentalist in a live band since bass guitar is integral to the structure and rhythm. A guitarist may play keys or saxophone or guitar/harmonica or banjo/mandolin in the same set of a band on different songs. A bassist can't stop playing too long.
Oh and I was a drummer before I picked up the bass guitar after a basketball injury to my ankle ligament.