Active pickups have a preamp which boosts the pickups and drives the tubes harder.

I've heard people going months without changing the battery. I change mine every month or so, because i play a lot and I'm paranoid about my tone.

Fractal Axe-Fx Ultra
EBMM JP7 Dargies Delight II
Manuel Rodriguez C Cedar Top
oh probly about every 6-10 months depending on how much you play.. BUT REMEMBER TO UNPLUG YOUR GUITAR when not in use LOL.... differents is, actives have a pre amp built in the pickup, thats how they get there insane amount of gain, there alright with solid state amps they do make a differents, i know i used to run them with a spider II , but they work best in a tube amp, where the pickups can drive the tubes to hell and back...... install the PA 2 with the EMG`s and your amp will start ripping peoples faces off. i LOVE EMG !!!
I do play around 5 or 6 hours a day but i've noticed a difference in tone after a month of playing, so i wouldn't go for 6 months without changing them.
And yes unplug your guitar, it will drain the battery if you dont.

Fractal Axe-Fx Ultra
EBMM JP7 Dargies Delight II
Manuel Rodriguez C Cedar Top
Actives are great for live playing because you get more of your tone from the pickup then the guitar. If you need to switch instruments they will all sound very close to each other. You could probably throw emgs into a squire and make it sounds hugely better, but it doesn't help the horrible craftsmanship. I don't prefer them though.
I Survived The "Silent Deftone Cocksucking Forum"!-August 15th, 2006
active uses a power source (i.e. battery), passive do not.
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?
just thought i'd throw it out there that the TS is a member of the LTD=LTD crusaders yet his sig says ESP ec-50

but anyway, i have emgs in my viper and i change the battery whenever i hear the tone becoming overly unclear/distorted.
i used to be a mod, then i took an arrow in the knee.