Your HOSTS file is one of the best preventers of ever going to BAD web sites.
I have made use of a hosts file before but found it can sometimes block ads that are wanted. For instance, there are times when researching best buys that Google ads are beneficial and I actually want to see them. Using a host file as it comes, there weren't even text links to ads. I had to go to the hosts file and remove any references to Google in order to see them. I'm not sure everyone would do that. I more rely on browser extensions to do the job now (Adblock). Extensions can be easily disabled when it comes to researching best buys and wanting to see the ads. Re-enable them when done. Other methods such as WOT, Norton DNS and Malwarebytes Pro look after blocking bad sites.