I played saxophone in school and for a few years thereafter, but once I picked up the bass my sax playing fell by the wayside. I still have it in case I want to play it again (and also because I'll never get back close to what I paid for it). I love the bass and play it almost every day. That being said, I went to a Chris Thile concert last night and I was exposed to how awesome the mandolin can be. I liked the sound a lot, plus I like the idea of having a small, portable, acoustic instrument that I can relax with on the porch or out traveling. The bass weighs ten pounds plus, and the amp is another 20 or 30 on top of that, and I can't play it without plugging the amp in (at least not audibly). Here's my concern: if I learn another instrument, then I'll be splitting my time between two instruments instead of focusing on one, meaning that I won't improve on them as fast as I would were I to choose one over the other. Also, I worry that they are just different enough to be confusing. The mandolin has differences in size, tuning in fourths instead of fifths, picking vs finger style, chords vs single lines, melody vs foundation/groove, and so on. So my question is this: as someone who works in a music related industry and wants to make music playing a big part of his life, do you focus on one instrument so that you can dedicate as much time to it as possible, or do you branch out and explore different modes of musicality despite it "diluting" your playing experience?