In answering this question, I asserted that programming knowledge has a half-life of about 18 months.
In physics, we have radioactive decay which is the process by which a radioactive element transforms into something less energetic. The half-life is the measure of how long it takes for this process to result in only half of the material to remain.
A parallel concept might be that over time our programming knowledge ceases to be the current idiom and eventually becomes irrelevant. Noting that a half-life is asymptotic (so some knowledge will always be relevant), what are your thoughts on this?
Is 18 months a good estimate? Is it even the case? Does it apply to design patterns, but over a longer period? What are the inherent advantages/disadvantages of this half-life?
Just found this question which covers the material fairly well: "Half of everything you know will be obsolete in 18-24 months" = ( True, or False? )