Service After Purchase 2004 Prius? Two Questions

Hello,

I just purchased a used 2004 Prius with 14,850 miles on it from a Toyota dealership.

It had been "certified" by the dealership prior to sale, and it runs well.

The oil and filter had just been replaced, as well as the tires rotated. It was also inspected, and perhaps had other things done.

It is still under the original factory bumper-to-bumper warranty.

The maintenance guide mentions that all that they are going to do is what was just done 150 miles previously.

I haven't asked the dealership these questions yet.

1.) As 15,000 miles is almost upon it, do you think I need to have a 15,000 mile service performed?
2.) Would it be prudent to have it serviced at 15,000 miles or wait until 20,000 miles (warranty issues)?

Thank you.

Robert