Meaning:

“余” means “remaining,” “额” here means “balance,” and “不足” means “insufficient.” The term, which was originally used to describe the status of a bank account, literally means “insufficient bank balance.” Now, the term is often used to remind people that they are running low on certain account balances, and to prevent the account value from draining down to zero, they need to top up.

For instance, when you use up most of the value on your phone card, you will hear “您的手机余额不足，请充值再拨,” meaning “You are running low on calling credit, please top up before you make a call.”

The usage has now expanded to other daily life scenarios to alarm people that something important is running out and they need to cherish it.

Example:

A: 你看见今天的新闻标题了吗？“晴天余额已不足, 下周起冬雨将回来, 气温也会降”。

Nǐ kànjiàn jīntiān de xīnwén biāotí le mā？ “Qíngtiān yú é bùzú，xiàzhōuqǐ dōngyǔ jiāng huílái，qìwēn yěhuì jiàng”。

Did you read the news? “Sunny days are numbered. Rain will return with winter chill next week.”

B: 太好了，终于有冬天的感觉了。

Tàihǎole, zhōngyú yǒu dōngtiān de gǎnjué le。

Great! It will feel more like winter.