Yes, you do. Sometimes a WordPress update and a plug-in update will clash, and create an issue that simply never existed before – so backing up your site before every update is very important. We do this as standard practice, so if there’s ever an issue we can quickly revert to the version that works, while we work through the problems. Don’t worry though, we do this all the time, and we’ve never come across an issue we couldn’t fix, not yet anyway!