In most cases, the best practice is to use an explicit save action. Autosave can lead to errors, even with low-risk operations. A good idea is to use autosave, but only with a draft version. In that case, show the user a message, e.g.: “You have unsaved changes: draft #1234” with the ability to use, discard or restore previous versions.
If the form affects some view, enable to work on a draft copy and allow see the preview without the need to save the changes.
Be consistent with that approach, so you won’t confuse the users with exceptions.
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