Rolling release doesn't mean that no testing is done. All updated packages are tested by maintainers before being released into the official repository. A rolling release simply means that there are no individually marked OS versions and you always get the latest packages.

In contrast, take Debian for example. It uses a point release system with major named versions (e.g. Debian 13 "Trixie"), minor point releases (e.g. 13.1), and security and bugfix patches between those. New feature updates are released only between point releases, and breaking changes are only introduced between major versions. This allows the maintainers to practice a greater amount of care in testing that the packages work well together, but also means that new features are always held back to some extent. This does not happen in a rolling release system. All upstream changes are pulled, tested, and released, regardless of whether a breaking change is introduced.

By its nature, a rolling release distribution will require a greater amount of maintenance. If a package update requires manual intervention, it will be published on archlinux.org. For as long as I've been a Linux user, I've only seen one package update that made systems temporarily unbootable, and I was saved from that by being a Manjaro user at the time.

But, to answer the question, I usually update my home and work PCs (both Arch) about once every week or two, or as required by a new software or important security update.