Thing I want to do

I want to instantiate particles and fire the instantiated ones in succession.
At that time, I want to be able to delete each instance in time.

Be in trouble

When I was investigating, there were "Delete when hitting a collider" and "Delete when the coordinates are exceeded", but I could not find anything like "Delete after x seconds".

Use an if statement

if (// after x seconds) {
    Destroy (gameObject);

I could write it in the form of, but I didn't know how to write it after x seconds in the if statement.

Particles are designed so that child elements appear after the parent element disappears.
Therefore, it cannot be used under conditions such as "collider" or "exceeding coordinates".