I've just had a massive clearout and sort through all my CC keeping in mind I cannot delete anything that one of my sims is wearing. I now want to save all my sims to an external hard drive.
Usually I would just export the sim as a Sim3pack. I'm assuming if I were ever to lose my game, reinstalling this Sims3pack would give me all the content attached to that sim. Right?

How do you guys backup your sims. Is there a better way of doing this?

A Sims3Pack doesn't include things that came as .packages. Nor does it include anything that doesn't also have a listing in DCBackup. If you want to be absolutely sure that your sim isn't going to be inflicted with something that EA substituted for something that is no longer in your game, you should save the CC as well.

If you have several sims, and you know the CC that they are using, I would make a folder, copy the sims to it, Copy the CC, add a text file noting which CC is needed for each sim, then (After checking to be sure that you've got everything) just use something like 7-zip to compress the whole folder.

And this will make it faster to install them if you want them back. Put the sims in the Saved Sims folder and the CC in sub-folders in Packages.

Thank you Ghost Sdoj. As of right now I have about 112 sims I want to save....so I guess its best to just make a back up of all my CC!

Also thanks for letting me know about the Sims3Packs not including .packages etc. I'd always assumed that was the whole point of it being a pack and it could've let me into trouble haha