If you’ve hosted a WordPress blog for any amount of time, you are probably familiar with the traditional upgrade procedure. It is fairly painless, but it involves downloading and copying files. If you have some custom files somewhere, you run the risk of forgetting one or two (like .htaccess) which might lead to undesirable results. Even when everything goes well, it still takes time to copy things around on your server.
There is a much easier way. By using Subversion, you avoid all of the downloading and copying. There are some excellent instructions for installing/updating WordPress with Subversion on the WordPress site. Once your blog installation is set up with Subversion, upgrading to a new version only requires one command–two if you make a backup, which is highly recommended.