Don't change horses at midstream.

1. proverb Do not try to choose or back a different political figure for an election after the decision has already been made or the position filled. Many people are dissatisfied with the senator's performance, but he will likely carry his party's support through to the next election—don't change horses at midstream, as the saying goes. The prime minister has been at the helm throughout the crisis. My thought is, don't change horses at midstream. Yes, wartime presidents are often reelected. "Don't change horses at midstream," as they say.

2. proverb By extension, do not make major changes to a situation or course of action that is already underway. I'm really not confident in the strength of my essay, but I guess I just have to see this one through at this point. Like they say, don't change horses at midstream. If you're about to close on a house, don't change horses at midstream and start looking at other properties! If you want your contractors to be able to keep track of everything, don't change horses at midstream and continually alter the renovation plans!