I'm experimenting with various apps and installing/deleting quite a few that I decide I don't want. I know you can 'junk up' a Windows PC by installing/uninstalling a lot of programs because often times outdated drivers or other settings are left behind. How 'clean' is the delete function on the iPad when I delete apps? Should I consider a hard reset periodically and reinstall things from fresh?

Bueller...anybody...?

When you delete using the iPad all the files are deleted, for example, The Sun app a daily news paper stores all the content as a PDF files. When deleted the pdf's all get deleted as well. In some cases the plist file may remain but that is just settings I think.

The uninstall is fairly accurate. There is definitely no need to reset your device to get rid of left over code, a reboot from time to time should be enough to keep your device running swiftly.

The sandbox mode apps are installed and function in, means that they cannot spread their data all over the device and can thus be easily fully deleted.

There is an iPhone viewing tool that lets you take a look at the structure if you are not a developer. It's fairly interesting. Each App is self-contained with it's own documents folder for storage.