> People overestimate the duration that their software will be used Please justify that. I did some software, a not too complex chunk of work for a midlands (

> People overestimate the duration that their software will be used Please justify that. I did some software, a not too complex chunk of work for a midlands (UK) retailer in 1999. It dealt with a couple of million pounds of retail orders that year. Not so big but not trivial either. It was still in use in 2015, and quite possibly is today (although the boss told me they re-used it for a rather different purpose by their sales reps). It was very reliable because I fought to keep it simple, and tested it brutally (eg. the core part took 5 days to write but got 3 weeks testing, founding only 2 errors, but it was 2 errors fewer). If it was crap it would have been junked so I'll claim that the end quality contributes to its life. High reliability tends to stick around. I think lex/yacc started in the 70s and is still around today in the form of its spiritual successors flex/bison. Ancient but still grinding along. ' In a 2008 interview, Johnson reflected that "the contribution Yacc made to the spread of Unix and C is what I'm proudest of" ' (https://en.wikipedia.org/wiki/Yacc https://en.wikipedia.org/wiki/Yacc) If you ship crap its lifetime is intrinsically much shortened. That's my thesis anyway.