Here's what it means:
* Frugal: Spending money carefully and wisely, avoiding waste.
* Banker: A person who works in the financial industry, often known for their careful management of money.
Therefore, "as frugal as a banker" means someone is extremely careful with their money, to the point of being as frugal as a banker is expected to be.
This phrase implies that the person is:
* Thrifty: They don't waste money on unnecessary things.
* Prudent: They make wise financial decisions.
* Cost-conscious: They are always aware of the cost of things.
Example:
"My grandmother is as frugal as a banker. She always buys things on sale and never throws anything away."