Would you write a 50 page term paper in Microsoft Word and never save it along the way? Of course you wouldn't! You will probably type one page and save it, another page and save it as you go along. Well you should be treating your WordPress blog like a Word document too! There are many reasons to backup your WordPress blog and make sure you always have a copy of it in case something goes wrong. Your database might crash, you might accidentally delete some of your posts or files, and you might even need to roll back to an earlier version of your WordPress blog. It's a simple fact that computers fail all the time. A hard drive might crash out and many people don't realize that your website is simply sitting on a computer somewhere that has all the same problems as your computer. That computer might blue screen, it might not turn on one day, the hard drive might stop. If the database crashes it might lose the entire thing. It might lose your several last year's worth of WordPress posts, comments, users, everything might be gone in a single second. But if you've backed up your WordPress site you can restore it later on and get access to it any time you want. Even if everything goes wrong, set it up again exactly the way it was. And even ignoring database crashes you might accidentally delete something. I know I do that all the time. You might delete the wrong comment, the wrong blog post and even empty the trash and never have a way to get that back. I know that sometimes even my webhost can be fixing a database issue and they will delete something without me having to do anything. So even if you think you're perfect and you never make a mistake you might delete something and it's better to be safe than sorry. It's worth taking time tobackup your WordPress blog so that you can get it back whenever you need to.
Totally agree with you. I've had so many problems with one of the hosting companies I am currently using. If you guys think, I will backup my blog/website later ... Check this article especially the part: Bad hosting companies – Real life examples http://www.ivanstips.com/how-a-bad-hosting-can-kill-your-business-real-life-examples/ So much crazy things could happen with your website while sitting on its server "comfortable", as your hosting company claims!
You can use a cronjob for it on your server, but there are also plugins which can help you with backing your install up. Example: https://wordpress.org/plugins/backupwordpress/