One word..... SAVE! Save multiple version of your scene when you make major changes, so you can revert back to whatever you need.

If you do that then frustrations like these will be in the past for you.

Artwork and 3DToons items, create the perfect place for you toon and other figures!

http://www.renderosity.com/mod/bcs/index.php?vendor=23722

Due to the childish TOS changes, I'm not allowed to link to my other products outside of Rendo anymore :(

Food for thought.....
https://www.youtube.com/watch?v=pYZw0dfLmLk