Why does iPhoto need to "repair inconsistencies" in my libraries after every time I quit and open it?
How about this: 

First, backup your iPhoto Library then quite iPhoto.  Then, hold down option + command while starting up iPhoto.  You should then get a prompt like this:



Try selecting all of the options if you have time (it takes a while to repair) or just the last option "Examine and repair iPhoto Library file permissions if you only have a little bit of time on your hands. Rebuilding your Library should solve the problem, but make sure to have a backup just in case something goes wrong.

For more reading, try this link here. Hope this helps!