Alright, so I plan on getting more expansion packs but I have custom content already installed. I've heard that if I download the expansion pack my custom content will disappear. Is there any way to stop this from happening? Or can I disable custom content before I install the expansion packs, and when I'm finish enable it again?

I've posted this question on yahoo answers with no help

remove the downloads folder from your documents and install the EPs and SPs then put it back again. or just copy and paste the downloads folder somewhere like the desktop, then install any EP or SP.

It won't disappear, but it may get temporary disabled. Re-enabling it isn't terribly hard - look in the Help section for information on it, if it happens (which it doesn't always - sometimes it's fine).

Whenever I've installed a new EP (but not a new SP, it seems), I've had to re-enable my CC, but it's never "disappeared," as in "been wiped from my hard drive." For some reason, I usually have to go through the re-enabling process two or three times before it actually "takes," but it always works in the end. Don't fret.

That's right - you only have to enable it again on the first screen that pops up, then exit and reload the game. The only time I've had the game wipe out CC is when I've uninstalled an EP. But a back up, either way, prevents any problem.