To make sure you know everything is good. That's why it's recommended to do a manual check of your mods and custom content. It may also false-flag files, making them look like they're bad when they aren't. Please understand, It will show conflicts between some files, but not all. There is a couple of tools to check mods/custom content.
This might be true for ModtheSims as well. If you are a member of Sims Resource allow you to look at your downloads history and download many files at once, I believe. The CC may need to be gone through and tested beforehand. – For Info: Be careful finding and downloading zipped custom content folders from Sims 3 youtubers, tumblr sites, etc.
