I back up my blogs frequently using a free plugin WP DB Backup. I will always restore my website if anything happens. I use my site to be scanned by WP Security Scan plugin and asks to be blocked by WordPress Firewall to how to fix hacked wordpress.
Everything you've worked for will proceed with this, should the server of your site go down. You'll make no sales, get signups or no traffic to your website, and in short, you're out of business until you get the site back up again.
Yes, you need to do regular backups of your site. I recommend at least a weekly database backup and a click over here monthly "full" backup. More. Definitely more if you make regular additions and changes to your website. If you make changes multiple times a day, or have a community of people which are in there all the time, a backup should be a minimum.
As I (our untrue Joe the Hacker) understand, people have far too many usernames and passwords to remember. You have got Twitter, Facebook, your online banking, LinkedIn, two blog logins, FTP, internet hosting, etc. accounts that all come with logins and passwords you will need to remember.
Change your password, frequently, or at least admin username and your WordPress password and collect and use other WordPress security tips to keep hackers official statement out!