Another important aspect to take into account concerns upgrades. With S/4 HANA on-premise you opt in – or not – to a yearly upgrade, while the cloud edition automatically enrolls you into a quarterly upgrade cycle. There are two time slots to choose from, and that is about the only freedom of choice there is. First you upgrade your testing environment, and then two weeks later the upgrade of your production environment inevitably follows. That means all flows need to be re-tested every quarter. So if you are considering downsizing your functional support team, keep the upgrades in mind to avoid overburdening the key users of the system with the frequent testing cycles.