How often should soil be changed out?

[Jace]

Regardless of live plants, because a vivarium is an enclosed eco-system, I would recommend doing soil changes. How often is going to depend on what exactly you have in the enclosure, and whether you do any maintenance inbetween changes (ie: removing any solid waste you do see etc.). As for throwing in a bunch of earthworms, it may seem like good practice, but the regular earthworms I buy to feed my African Bullfrogs need to be kept in the fridge otherwise they tend to die and decompose rather quickly. Any worms that have escaped being eaten I usually smell a few days later as they cannot go deep enough to find cooler temperatures and subsequently perish. It's also a good idea to regularly check live plants...I have had a few in my Fire-bellied toad enclosure outgrow their surroundings and I have had to take them out, trim their roots and stems and then allow them to soak up some much needed nutrients outside the vivarium before replanting. I would not have known unless I changed the soil. So, based on my personal experience, I would have to say: change the soil.

[Paul Rust]

Nothing wrong with what Jo-Anna said. Just to add to it "hope you don't mind"
I usually don't change it unless I do remodel. I add more to it when I change the worn out moss with new and trim the plants.

[Kurt]

I will second what Paul said. With live plants in it, I wouldn't change the substrate unless it became really disgusting and it shouldn't.

[Jace]

Rereading my previous thread, it sounds like I'm advocating frequent soil changes. Definitely not the case! Even though I recommend doing soil changes, I only do them when necessary, such as when my plants are suddenly dying or a frog is unhealthy, as you never know if there is something in the soil contributing to a problem. Otherwise, I pretty much leave it alone. I'm still new to the whole live plants thing, so I'm learning as I go!

[Socrates]

This is why I recommend adding spring tails, pill bugs, and/or earth worms to your soil. They not only help cycle the soil, but can be a tasty treat for your inhabitants. BUT be sure they are collected from a pesticide/herbicide free area and/or raised yourself. In my tanks, I only add new soil if I'm adding more plants or reconstructing the enclosure.