3-hour old wet cat food in bowl? Your cat might prefer it.

My personal experience tells me that if you put down a sachet of wet cat food into a cat food bowl and your cat rejects it for whatever reason, you should cover it up with a plate (stop flies laying eggs) and wait at least a few hours depending upon the ambient temperature because your cat might come back and eat it. In fact, it can be left for much longer depending on the air temperature and your cat's preferences.

He might do this because (1) he is a little hungrier three hours later and (2) the food is a little smellier. And some cats are more dependent on others on the food being smelly. Some cats, also, are more naturally scavengers and they don't mind if the wet cat food smells a bit.

My cat eating 3-hour old wet cat food.

The advantage of using this method is that you throw away less cat food. Throwing away a full bowl of cat food or even a half full bowl is troublesome for two reasons (1) you are wasting money and in this era of cost-of-living crisis you don't want to waste money even pennies and (2) throwing away substantial amounts of wet cat food is problematic because it smells. 

You put it in the waste bin, but it smells and sometimes flies deposit their eggs on the food before you can throw it away which results in maggots crawling all over the place. You don't want to throw away wet cat food you can help it.

Wet cat food bowl used for 5 meals without washing it. Image: MikeB

And on occasions, when you put down just the right amount of wet cat food and your cat is nicely hungry, he will eat everything in the bowl, and you will not even need to clean the bowl in preparation for the next helping of wet cat food!