How do you back up photos?
This is a question you should ask any photographer you work with -- losing photos, especially of your wedding, is a terrible feeling.
My camera has two memory card slots -- for every wedding and session, both of those cards are capturing the same images. That way, leaving the wedding or shoot, I already have two copies of each image.
When I get home, I immediately back those cards up to 3 external hard drives, and 1 online back up system. Until I have delivered your photos to you, I do not delete the images from either memory card, so your photos are in 6 places.