Do I need to take the lense off my DSLR?

I got my first DSLR a month ago, a nikon d3100. I've shot with other DSLR's and took classes before but I never actually owned one so knowing how to treat and store them is my downfall.

I only have one lense, is it okay to leave it attached to the body 24/7 or should I keep taking it off to store it?

Unless you intend to bump it around a lot, it is fine to leave the lens on all the time.

Mine's been attached to my D200 for the past four years or so. The whole thing sits on the tripod, covered with a Harley bag to keep the dust off. They aren't that delicate.

You will want to leave the lens on. Every time you remove the lens, you chance getting dust in the camera and/or on the sensor.

While these cameras are intended to interchange lenses, doing so needlessly just increases the chance of dust.

No, I keep mine on 24 / 7. Taking it off when not necessary risks getting dirt / dust into thrbaa

Leave it on. That is the best way to keep dust out.