Hi - I'd suggest that you might want to have a look at this article. It gives you a good insight as to SAAS v on-premise solutions etc

www.workbenchcentral.com/blog/on-premise-cloud-hosted-saas-what-does-it-all-mean-and-what-is-right-for-me

Whilst it's the way that a lot more suppliers seem to be going, if you think about this in with your procurement hat on - and that is what's going to happen at the end of 3-5 years - it's tough to see you doing anything but just rolling this over (and over and over again) as someone else has all of your data on their server.

At the risk of being awfully contentious, my own experience is that in a lot of circumstances, there's little consideration of whole of life costs - especially with that thinking about what's to happen in 3-5 years. Right now, many of these purchases done right now are flying under the radar of procurement teams because they're below procurement limits or just being called operational expenditure within business delegated authorities.

That said, one of the benefits that I've also seen is that upgrades happen automatically on the server of the host without the business having to create teams to do this, especially where there was a major upgrade - which were previously a big financial impact on many businesses.

Hope that this is useful.