Interesting to see how this has evolved: see "Why Roll-ups Fail" on Shareslide https://www.slideshare.net/cycam/why-rollups-fail-cycam-pty-ltd-v20191?qid=8a22964c-a17f-4cbe-a8a6-752cfae70f63&v=&b=&from_search=1Lots of boxes ticked.