I back up my blogs frequently using a plugin WP DB Backup. I can restore my website to the last settings if anything happens. I use my blog to be scanned by WP Security Scan plugin that is free frequently and WordPress Firewall to block requests to secure your wordpress website.
No software system is resistant to vulnerabilities and bugs. Security holes will be found and bad men will do their best to exploit them. Keeping your software up-to-date is a good way to stave off attacks, once security holes are found, because their products will be fixed by software vendors.
You should also set the"Anyone try this web-site Can Register" in Settings/General to off, and you should have some type of spam plugin. Akismet is the old standby, the one I use, but there are lots of them these days.
BACK UP your website regularly and keep a copy on your own computer and off-site storage. Back up daily if you have a very active website. You spend a whole lot of time and money on your site, don't skip this! The one complete solution that does anchor it all is BackupBuddy, no back up your documents, widgets, database and plugins. Need to move your website to another server, this will do it in see this website less than a few minutes!
Bear in mind that the safety of your blogs depend on how you manage them. Be sure that you follow these basic strategies to avoid hacks and exploits on your blogs and sites.