The idiom comes from the danger of switching horses while crossing a river. Doing so could easily lead to a fall and drowning.
It is often used to warn against making changes in the middle of a challenging situation, especially when it seems like the end goal is within reach. The phrase implies that it's better to stick with the current course, even if it's difficult, rather than risk failure by changing directions.
Here are some examples of how it can be used:
* "The team was struggling, but the coach refused to change horses mid-stream and stuck with his original game plan, which ultimately led to victory."
* "The company was in the middle of a major project, so they decided not to change horses mid-stream and stick with the current CEO."
* "It's tempting to change horses mid-stream when you're not seeing the results you want, but it's often better to stick with what you've got and see it through."
The meaning is often negative, suggesting that changing course can lead to chaos and failure.