Notes:
If you look further into the Agile manifesto, you will find that in addition to the four key values there are twelve principles that “support them”. I find there is a difference: while I find that most of the key values are applicable most of the time, the principles are less generally applicable.
I'm going to run through the principles fairly quickly, and comment on when they are applicable and how common this is in my experience. This is the first principle...
There are a number of assumptions hidden in this appantly reasonable principle:
That there are sufficiently reduced subsets of the full system that are “valuable software”;
That the cost of “continuous delivery” is justified by the value of the delivery; and,
This will satisfy the customer.
Far more often, I find that a large part of a project is a supporting infrastructure without which the system has no value, that UAT and “roll out” of new version is an expensive disruption to the customer's business, and that the the customer really wants us to “go away and come back when it is finished”.
Very seldom do I find a customer wanting to “roll out” an incomplete version of the final system – and they receive no business benefit until after the roll out.
Note:
I am aware that this principle is sometimes “translated” to mean delivery to a testing team – but while that has benefits to the development of software it hardly “satisfies the customer”.