True. The shelf-life refers to how long one cares to remember the technology. The unfortunate fact is that these techs are so specific that I simply forget them

True. The shelf-life refers to how long one cares to remember the technology. The unfortunate fact is that these techs are so specific that I simply forget them weeks after I don't have to use them any more. The entire Uber engineering team had to endure the horror of writing hundreds of lines of oh-my-god-it's-so-cool-dsl Puppet for simple deployment tasks and waiting for on average 15 minutes before a change took place. Guess how many people missed Puppet when it was ripped off Uber's infra? Probably only the dude who thought Puppet and Graphite were the best systems in the world. And guess how learning the intricacies of Puppet helped anyone's career or ability to build better systems down the road? The answer is zero and zero.