No, I do not need any more than one bass. I just want a single vintage style P-Bass if it comes down to having just one. But I'm a hobbyist/collector/tinkerer as well as a player, and I like having some variety just for fun.
The funny thing is that I am primarily a bassist, and less of a guitarist (though I am quite competent on guitar). I play bass in a band, but not guitar. Yet I have a handful of basses and probably two dozen guitars!
FWIW, my basses are:
'76 Musicmaster, Oly white
'77 Stingray with '80 Sabre fretless neck, clear
'96 L-2000 fretless, clear
Frankenstein early '60's style P-Bass (MIJ+MIA parts), black - my main bass for years
AV '58 P-Bass, blonde (newish to me - under a year of ownership)
AV '64 Jazz Bass, Oly white (newish to me - under a year of ownership)
...and three builds in the works:
Extra long scale slab P-Bass (Charcoal Frost)
Accurate repro slab P-Bass (Midnight Wine over BSB, with white painted black Bakelite guard)
Single-pickup J-Bass, "alternate universe" style, as if J's had existed in the '50's (Inca Silver with single ply white guard and one piece maple neck)
The only redundancy there, from the point of view of features, is between the G&L and the Music Man. There are both active, both fretless, both ash bodies with maple necks and ebony fretboards – and hell, they are even both clear finishes! The two P-Basses are very different, one being basswood with rosewood board, and the other being ash with a one-piece maple neck. Also one has a vintage style pickup and the other has a 1/4 Lb. The Jazz and the Musicmaster are obviously different from everything else there. So my master plan is to strip the L-2000 and have it refinished in 3TSB by MJT, with no aging, and have frets added to the neck (or have G&L make me a new neck to spec – but $900 is a bit steep). That way I have a fretted active bass and a fretless active bass, with different paint jobs, instead of two fretless active basses with the same paint job.