No dust gathering, each bass gets used, but I have multiple basses mainly because...
To stop the voices in my head.
They keep telling me to mod my basses, but they also keep coming up with cool new ideas for different basses / different mods so I will continue to buy basses when I can afford to do so.
["Pssst, hey! That bass is cool, but it doesn't come in the right colour; that bass would sound really good with this pickup combination; nobody has done that combination before; you don't have that kind of a bass, you've never even tried one like it, try it and see; what if you get a gig where you need to...; that song would sound good with a bass that has..."]
If I sacrifice enough basses (a couple dozen ideas yet to go) to the madding mod gods, then maybe the voices will finally shut up and I can get some peace.
Seriously though... If I could only afford beans & rice for every meal, then that's what I'd eat and live. If I could only have one bass, I'd live. Luckily, I'm not an impoverished packrat and can afford the spice of life, variety.