An aspect of procurement contracts, in fact most contracts, is that not much thought is given to what happens at the end.
For some contracts, it does not matter.
For many, especially those relevant to an ongoing enterprise, it does. From my observations, often sufficient thought of retiring and replacing contracts for supply of goods and services not given early enough.
It should be.
One of the best illustrations of that, and I mean illustration, is as page 3 of the 2012 Commonwealth of Australia Better Practice Guide “Developing and Managing Contracts” “Getting the right outcome, achieving value for money” at http://www.anao.gov.au/html/Files/BPG%20HTML/Developing%20and%20Managing%20Contracts/resources/ANAO-DevelopingManagingContracts-BPG.pdf, there is a great schematic which, for me, says it all very succinctly and in a way which reflects the cyclic nature of procurement.