You only really find out the true value of backing up your slideshows when you get stuck without a backup. Here are some suggestions:
1. Back up your most frequently used presentations on a disc (CD or flashdrive preferably)
2. Keep a set of overhead transparancies with you (they may be outdated, but failing all else, they beat having no show at all).
3. Ensure that another IT literate person whom you trust has separate backups of your shows – they can then simply email them to you if something goes wrong when you’re away from your base.
4. Have a plan B. Can you continue without your slides?
Remember to refresh your backups when you update your main shows.