Helm chart best practices : latest tag or not

I think this is a choice that comes down to the needs of your project. An interesting comparison is the current versioning strategy of the public charts in the Kubernetes charts repo and the current default versioning strategy of Jenkins-X.

The public charts only get bumped when a change is made to the chart. This could be to bump the version of the default image tag that it points to but each time it is an explicit action requiring a pr and review and a decision on whether it is a major, minor or fix version bump.

In a Jenkins-X cluster the default behaviour is that when you make a change to the code of one of your microservices then it's chart version is automatically bumped whether or not the chart itself changes. The chart in the source repo refers to a snapshot but it is auto deployed under an explicit version and that version gets referenced in the environments it is deployed to via a pipeline. The chart refers to a draft/dev tag of the image in the source and that's also automatically replaced with an explicit version during the flow.

The key difference I think is that Jenkins-X is driven towards a highly automated CI/CD flow with particular environments in the flows. Its approach makes sense for handling frequent deployment of changes. The public charts are aimed at reusability and giving a stable experience across a hugely wide range of environments and situations through public contributions. So the strategy there is more aimed at visibility and ease of understanding for changes that you'd expect to be less frequent by comparison.