Simple Examples:
* The old house deteriorated rapidly without proper maintenance.
* Her health deteriorated after the accident.
* The quality of the food deteriorated over time in the fridge.
More Complex Examples:
* As the economy deteriorated, unemployment rates soared.
* The relationship between the two countries deteriorated after the trade dispute.
* The patient's condition deteriorated so quickly that the doctors had to operate immediately.
Figurative Example:
* The once-thriving city center deteriorated into a desolate wasteland.
You can use "deteriorate" to describe a gradual decline in quality, condition, or state. It emphasizes the negative process of worsening over time.