How well does sushi keep?

Excuse me, I'm curious about the shelf life of sushi. I understand that it's a perishable food item, but I'm wondering if there are any specific factors that affect how long sushi stays fresh. For example, does the type of fish used, the preparation method, or even the storage conditions play a role in determining the longevity of sushi? Could you please elaborate on this topic and provide some guidelines on how to ensure that sushi remains in optimal condition for as long as possible?