Lindy effect

The Lindy effect is a theorized phenomenon by which the future life expectancy of some non-perishable things, like a technology or an idea, is proportional to their current age. Thus, the Lindy effect proposes the longer a period something has survived to exist or be used in the present, it is also likely to have a longer remaining life expectancy. Longevity implies a resistance to change, obsolescence or competition and greater odds of continued existence into the future. Where the Lindy effect applies, mortality rate "decreases" with time. The concept is named after Lindy's delicatessen in New York City, where the concept was informally theorized by comedians. 
The Lindy effect applies to "non-perishable" items, those that do not have an "unavoidable expiration date". For example, human beings are perishable: most humans live for about 80 years. So the Lindy effect does not apply to individual human lifespan: it is unlikely for a 5-year-old human to die within the next 5 years, but it is very likely for a 70-year-old human to die within the next 70 years, while the Lindy effect would predict these to have equal probability.
History.
The origin of the term can be traced to Albert Goldman and a 1964 article he had written in "The New Republic" titled "Lindy's Law". The term Lindy refers to Lindy's delicatessen in New York, where comedians "foregather every night at Lindy's, where ... they conduct post-mortems on recent show business 'action'". In this article, Goldman describes a folkloric belief among New York City media observers that the amount of material comedians have is constant, and therefore, the frequency of output predicts how long their series will last:
Benoit Mandelbrot defined a different concept with the same name in his 1982 book "The Fractal Geometry of Nature". In Mandelbrot's version, comedians do not have a fixed amount of comedic material to spread over TV appearances, but rather, the more appearances they make, the more future appearances they are predicted to make: Mandelbrot expressed mathematically that for certain things bounded by the life of the producer, like human promise, future life expectancy is proportional to the past. He references Lindy's Law and a parable of the young poets' cemetery and then applies to researchers and their publications: "However long a person's past collected works, it will on the average continue for an equal additional amount. When it eventually stops, it breaks off at precisely half of its promise."
Nassim Taleb presented a version of Mandelbrot's idea in "The Black Swan: The Impact of the Highly Improbable" by extending it to a certain class of non-perishables where life expectancy can be expressed as power laws.
In Taleb's 2012 book "Antifragile: Things That Gain from Disorder" he for the first time explicitly referred to his idea as the Lindy Effect, removed the bounds of the life of the producer to include anything which doesn't have a natural upper bound, and incorporated it into his broader theory of the Antifragile.
 According to Taleb, Mandelbrot agreed with the expanded definition of the Lindy Effect: "I [Taleb] suggested the boundary perishable/nonperishable and he [Mandelbrot] agreed that the nonperishable would be power-law distributed while the perishable (the initial Lindy story) worked as a mere metaphor."
Pareto distribution.
Lifetimes following the Pareto distribution (a power-law distribution) demonstrate the "Lindy effect". For example with the parameter formula_1, conditional on reaching an age of formula_2, the expected future lifetime is also formula_3. In particular, initially the expected lifetime is formula_4 but if that point is reached then the expected future lifetime is also formula_4; if that point is reached making the total lifetime so far formula_6 then the expected future lifetime is formula_6; and so on.
More generally with proportionality rather than equality, given formula_8 and using the parameter formula_9 in the Pareto distribution, conditional on reaching any age of formula_2, the expected future lifetime is formula_11. Example: for formula_1 or formula_13 the expected future lifetime is formula_3.
The Lindy effect, according to Iddo Eliazar,
is connected to Pareto’s Law, to Zipf’s Law, and to socioeconomic inequality.