You should service the battery annually or when you notice the "battery" light comes on, or when there is difficulty starting the engine.

您应每年检修一次电池，或者在注意到“充电”灯亮，启动汽车很困难时检查电池。

youdao

The difficulty comes when you do not know what garbage looks like.

ECONOMIST: Statistics and climatology

Rather, the risk comes from the difficulty of finding good investments when the money from investors starts rolling in.

WSJ: Book Review: The Hedge Fund Mirage

Was he referring to the difficulty that some societies have, some communities have now when it comes to committing people against their will?

WHITEHOUSE: Press Briefing by Press Secretary Jay Carney,