i have 5 at the moment. They all do different things... they sound, look and play different to each other. It's nice to have options. 
 
I have :- 
 
Classic Jazz (pasive) 
Precision (passive) 
Modern Jazz (active / passive) 
Dual Humbucker (active) 
Electro Acoustic Bass. 
 
Could do with a fretless, an EUB and a DB so I have all bases (basses) covered   (But even then will still probably want more!)