Do you ever need to replace old driftwood?

I've never had to replace wood but most of the big wood I have are pretty thick so I think it will end up deteriorating pretty slow. I have some twiggy looking manzanita branches and most of them are rotting away slowly since they're so small.
 
Wood lowers the pH, not raises it. It releases tannic acid into the water, making it softer.

BAHAHAHAHA! This is what you get when I post to early in the morning, lol. That's my excuse and I'm stickin' to it! :D
 
AquariaCentral.com