This one was suggested to me by my friend and colleague Mike Koffman. He always tries to take the time to go to Advanced in the Modify Web Part panel and take away the user’s ability to "close" the web part. Here’s the story why.
In working on other people’s sites in SharePoint, I’m often amazed at how many Web Parts are on the pages, but not visible to the users. This is usually due to false starts in implementation, trying things out and then abandoning them for some reason, etc.
Most people seem to just click the little "X" in the upper corner of the Web Part and assume that it has been deleted. But no, it’s still there. If you open the page in SharePoint Designer, you’ll see all of the "ghostie" Web Parts still hanging around. (I say "ghostie" because they are faded out in the UI. And because I have a four year old.)
Because the Web Part is still there, SharePoint still has to process it when the page loads. I heard through the grapevine that a Microsoft engineer said recently that it takes more work for the system to process the Web Part when it’s closed than it does when it’s visible, but I can’t vouch for that. In any case, SharePoint has to at least read the code for the Web Part to realize that it shouldn’t display it.
To really get rid of the Web Part, you should select the "Delete" option from the menu rather than clicking the "X". The problem is that, once it’s closed, it’s virtually invisible so you don’t even know it still exists. One trick you can use is to navigate to the page and add "?contents=1" to the end of the URL. This gives you a page with a list of all the Web Parts on the page, with a column showing whether the Web Part is open or closed. To get rid of the closed Web Parts, select the check boxes next to them and use the "Delete" option on the toolbar. The other option is the one which I prefer: open the pages in SharePoint Designer and delete those little "ghosties"!