As jester posted, 25 gig runtimes is definitely not the way to go.  I tend to create project runtimes for 1 time use then delete or transfer them to disk.  It keeps my drive uncluttered and manageable.  And it just came to mind, don't discard your original zip or installer files.  Transfer them to a safe place and find a way to catalog what you have.  Content does have a tendency to accumulate rather fast and the last thing you want to do is lose that one item you would like to use down the road.