I hate it when people say, “It’s not a sprint; it’s a marathon.”
I understand what they’re trying to get at, and I think it generally comes from a good place. Don’t kill yourself trying to get ahead when there is always more work to do.
Having said that, my brain always defaults to, But the first guy to run a Marathon… from Marathon to Athens to announce defeat of the Persians… died pretty much as soon as the words left his lips (supposedly – who really knows; Greek historians were drama queens). This mortality is completely counter to what the saying means, since the point is not to kill yourself, by referring to something that the first person to successfully finish the task dropped dead from performing the feat, I feel like it’s not a good metaphor.