Constant effort yields sure success.

功到自然成。

《新英汉大辞典》

The secret of invention is constant effort.

发明的秘诀在不断的努力。

youdao

There is no constant success without constant effort.

只有永远的努力，没有永远的成功。

youdao

Or they assume that it will require a steady, constant effort over years.

FORBES

When the parties were here earlier in the year, we said this was going to require constant attention and constant effort.

WHITEHOUSE: Press Briefing

And because of high rates of attrition (casualties and retirement, but mainly protracted absence without leave), just maintaining those numbers requires constant effort.

ECONOMIST: The war in Afghanistan