It’s so tedious to keep all dependencies updated to their last version that I doubt most projects actually are, although it should be considered as important as any other audit. If you don’t want to actively keep an eye on your David badges and manually edit your package.json for dependencies updates, a good solution is Greenkeeper.
It knows your package.json and monitors the NPM feed. Whenever a new stable version of a dependency you project uses is released, it runs your CI tests against it, opens an issue if your CI tests fails, or opens a PR if the new version is out of range for the SemVer you specified. The detailed explanation is here.