I love a good turn of phrase. I also love the age they imply. If you say "I'll be there in a jiffy" you give a different impression than if you say "OMW" or "I'll be there in two shakes of a lamb's tail".
I'm fascinated by where phrases like that come from, how they age, and how they die. Recently, I was describing a problem and a potential solution and said, "it looks promising, but it's no smoking gun". Then I wondered if guns even smoke any more. Was that a phrase that came into being when black powder was measured by hand? Or did guns just smoke more in the early 20th century?
What were the phrases in the middle ages that have been completely lost to history? Something involving horses or tools that we don't use any more? I think of the phrase "changed horses in the middle of the stream", which isn't that old, but just isn't as commonly useful as it might have once been.
What about the future? Just as OMW and other text-isms became common, advances in technology will certainly change language, too. If you need to get somewhere in a hurry, maybe you'll say, "let's JohnnyCab" for taking a self-driving car, just like we've turned other technology into verbs ("Google it", "let's Uber there"). At a crime scene in the future, maybe cops will say, "it's a good lead, but it's no super-heated fusion coil".