Retrospectives are uncommon
Something I have been mulling over as a result of this entry (and being prompted to write it) is how uncommon retrospectives are in writeups of things. Over the years in all of the usual sources, both old and new, I've seen quite a lot of writeups of the form 'this is the shiny thing that we've implemented and here is our short term experiences'; heck, I've written any number of them myself here on WanderingThoughts. But I've not seen very many looks back after a year or three, or after people have had the chance to do a second version of whatever system (or at least considered and rejected doing it).
(This pattern has more or less held true well before people started writing blogs; I am pretty sure I saw much the same effect in LISA proceedings in the early and mid 1990s.)
Writing up things when they are new and novel and you are enthusiastic about it is not a bad thing, and often retrospectives are less interesting than the original writeup (especially when everything works well). But I suspect that there's usually something interesting that's learned after a year or two, and I have to wonder how much we're missing by not writing and publishing retrospectives more often, or at least thinking about them.
A retrospective has a lot of potential ground to cover even if things went well in general. What worked and what didn't? What surprises came up? What would you change if you did it again? What important thing turned out to be missing, or conversely what did you spend a lot of time on that turned out to be unnecessary?
(When things turned out not to work out after all, a retrospective is even more interesting although often more painful to write.)
And even if the answers to these questions are all boring or you don't write anything up in the end, I think that there's clearly value in regularly looking back at our work this way. For better or worse, a lot of system administration is relentlessly forward looking; if something is working well enough, it's easy to put it out of our minds even if there are things we could learn from it.
(Having said all of that, I have no idea if I'll have the time and energy to put this into action on any of the various things I've written up here. Which neatly illustrates the problem with all of this; who has the time?)