The Finder's information should be refreshing automatically and instantly as files and information is changing that is the goal and why Apple does not provide a "Refresh" option, although in practice things sometime don't work for whatever reason.
If the information is not automatically updating changes to files etc, it may be the result of a bug or Finder preferences corruption, or other corruption.
Make sure you are running the latest version of OS X, as the issue may be a bug that has been fixed already.
Additionally for folders where the contents are not updating properly it might be a good idea to try and remove the .DS_Store file for that directory, and see if that has an effect. (restarting the finder to verify)
The next option would be to reset the Finder's preferences. Try removing the the file named com.apple.finder.plist located at
~/Library/Preferences/com.apple.finder.plist (restarting the finder to verify)
If the problem is consistently occurring contact Apple and show them the issue and how to repeat it, you may have found a bug.