Reasons why you might want to back up your blog would be:
1. Blogger deletes your blog.
2. Journal Keeping.
3. Blogger Deletes your blog.
4. Just because you have nothing else to do.
1. Posts
2. Template
3. Photos
4. Comments
From Blogger: How do I import and Export blogs on blogger. You want to export your blog to store it on your own hard drive or switch it to another service.
From your dashboard click on settings. This is what you will see.
Now you are going to click on Export Blog. This is what you will see.
Now you just click on Download Blog. I have a Mac, so it automatically started downloading for me. I imagine for you PC users out there you will get a pop up window asking where you want to put it. Decide on a place, and then click, “save.” This is as far as I have gotten. I have my entire blog, all 2348974573 megabytes stored somewhere on my computer. I’m feeling a lot better.
This is all I know! Anything more technical I would consult Google!