Backup/Test Site - Best Practices

[Replicant]

I do a .htaccess password protect on my test directory as per the license requirement (Second instance of the script can't be accessible to the public). I backup my current forum and do whatever testing, mods, tweaks and so forth without any updates until the next version comes out. I then upgrade my test database with my mods and tweaks to make sure everything is working with the new version, then upgrade the live site. I use custom themes on my site and since they have to be updated as well to maintain compatibility, I uninstall those before upgrading then reinstall the new version once the upgrade is finished. I found that most of the errors I encountered will upgrading were due to the system trying to process custom templates.