Print the worksheet to paper or a pdf.  Then go ahead and delete it.  Save the printed copy for the day that property is sold.  It doesn't really serve any purpose lingering around.

I code it to form 17 4562 only then I put a 99 for depreciation so it no longer calculates depreciation.  Those then print out every year with the clients tax return, that way if they move or use a different preparer that tax preparer has that information.  That great if you just print a copy and keep in your file, but in my office I have had them purge files including the back-up accidentally.