Some changes are being case to warn users about notebooks which haven't been accessed in some time (3 weeks) and automatically suspend them given a further grace period. The reason for this and the explanation of how it works can be found here https://datalab-docs.datalabs.ceh.ac.uk/howto/suspend-and-restart-resources/. An example warning will be shown for a week before the notebook is suspended as seen below. Note that once suspended a notebook can easily be restarted with no data/configuration loss via selecting "Turn On" after choosing the ellipsis, so this should have minimal impact.
Please don't hesitate to get in touch with us if you're unsure about how this works or have a special requirement for your project.