This Russian expression came up in a different Russian/English forum (on Facebook). There are at least four expressions in English that have a somewhat related meaning:
The difference is that the first two might be said by someone who is against a new idea or solution, while the second two are said in response to critics who object that the proposed idea or solution is less than optimal."If it ain't broke, don't fix it."
"Leave well enough alone."
"Don't let the perfect be/become the enemy of the good."
"It's close enough for government work."
In other words, one could use the first pair of expressions to attack a new idea, and the second pair to defend the same new idea.
Examples:
JOHN: "What do you think of Obama's plan to reform the health-insurance system in the US?"
JANE: "I think the system we have now works well enough, despite its flaws -- if it ain't broke, don't fix it."
TOM: "I think gays and lesbians should be allowed to adopt children."
HARRY: "But surely the best possible environment for kids is with a mother AND a father?"
TOM: "True, but why let the perfect be the enemy of the good?"