What are the advantages to upgrading a bridge on a bass? I have a mexi Fender Jazz that I love, and am considering upgrading as I will be using it for some time. However, I'm not sure if upgrading the bridge is worth it, and if so, what bridge I should upgrade to. I heard good things about the Badass bridge but also heard you have to file your own saddles, which worries me.
It's a difficult one - some people claim that changing the bridge will make some massive tonal improvement, and others say that this is only the placebo effect, and any tonal difference created would be inaudible.

I am personally in the second group, and think that unless you are having problems with your current bridge (such as the saddles not staying in place), then there is no reason to change.
Current Gear:

Warwick Thumb BO 4
Musicman "StatusRay" Stingray 4 - Carbon Fibre Neck
Musicman Stingray 5 HH
Sadowsky MV4 Jazz

Markbass LittleMark II
AccuGroove Tri12l
Sansamp VT Bass
Line6 BassPodXT Live

From what I gather it's a mixed feeling on the bridge upgrade. The biggest reason seems to be for increased sustain, which I've never felt like I needed more of, and seems to generally be undecided if it indeed does provide much more sustain. My telecaster and mustang bass are both string through and that I think does more than anything. From that angle, I think a bridge is upgraded because you have money and need to spend it.

The reason I think warrants a bridge upgrade is intonation, basses like the dano with a rosewood piece, or the 3 post Epi EB-0 basses really aren't the best, and some people take issue with the 2 saddle style bridges on some early fenders. For the record I just bought a bronco that has sat in a pawn shop for at least two years, and it's intonation was spot on as well as the action, better than anything I've played.

These are just my opinions remember, but I think most people can agree unless you have lots of excess money to spend, the bass itself, strings, and the amp all play a wayyyy more vital part in your tone, that the bridge just doesn't occupy.

I.E. if you are playing a 20 year old budget P bass copy from a pawn shop, through a bass practice amp you have bigger troubles.