You may want to take a backup of your blog for many reasons. May be you are moving to a new platform (Blogger to Wordpress for example), may be you keep accidentally deleting your posts or may be you just want to be safe, in case. But Blogger does not have any tool which provide bloggers to backup their blog. But here's a feature built right into Blogger which can be used as a way to backup your blog posts. Well this doesn't involve any third party tool and its not a full fledged back up solution. However it is effortless on your part and is effective as you will have a back up of all of your posts. It involves the BlogSend feature of blogger.
To enable this feature, login to your Blogger account, and from your dashboard click on Settings --> Email. You will see two fields here the 'BlogSend Address' and the 'Mail-to-Blogger Address'. The 'Mail-to-Blogger' Address is the email you set up to create a new post just by emailing to that address. For now our concern is the 'BlogSend Address'. Enter your email address here and save the Settings. Once you have set up 'BlogSend with your email id, every new post that you make would be emailed to you. Don't set up more than one email id as the posts would be sent only to one email address. This way you would have a backup of every post of your blog right in your inbox. Create a separate folder for those emails and save them in that folder for easier access when you need them.