Yep. Agreed. Batteries will generally last six months to a year, depending on how much you use the instrument. The battery powers the "active" electronics, which usually includes an active EQ. Changing batteries is usually very easy, at most you'd need a screwdriver. Some basses use one battery, some use two. In the vast majority of cases those would be 9v transistor radio batteries.
Here's a couple of things to watch out for. The most important one is, what happens when the battery dies. Or, more specifically, "how" it dies. Some basses are more graceful than others in that regard. Some will die "instantaneously", and in others you'll be able to hear it long before it happens (usually the volume will decrease and you'll hear some distortion that wasn't there before). The thing to do is, pay attention the first time this happens in your bass. Then, you'll know what to expect.
A good thing would be, a passive bypass. That way, if your battery ever dies unexpectedly, you can just switch over to passive mode and keep playing. If your bass doesn't have a passive bypass, they're usually very easy to install. You can do it yourself if you're handy with a soldering iron, or you can bring it to a tech and they'll probably do it for the minimum bench charge.
There's no reason to be overly concerned about the battery. My approach is this: I keep an extra new battery with me at all times, in the gig bag or in the instrument case. And, I keep a screwdriver too, if the bass needs one (for those that have the pop-up battery compartments, you don't have to worry about this). If I have a session or a super-important show, I'll always change the battery and put in a fresh one a few days before the gig. And, on general principles I rotate out the old batteries every three months or so (I play "a lot", and over the years I've found that three months is the beginning of my risk period for some of my active basses, so once every three months or so I spend an hour or so and change the batteries in "all" my basses, that way they're always ready to play on demand).
But, this thread is about PASSIVE basses.
Just kidding, you can talk about whatever you want. So far, you guys are compiling a great list of passive bass benefits. Anything else we haven't thought of yet, in terms of why people go passive?
