My favorite instance of this is bugs in open source projects. I worked briefly in streaming video - like for 3 months - and in that time concluded that the very, very, very old bugs in ffmpeg actually constituted some of the most reliable behaviors on which I could confidently depend.
To me as a physicist, the effect seems "natural" from a dimensional analysis point of view: If the current age is the only time-dimension variable you know, the odds are that other time-dimension variables like life expectancy are proportional to it