Feeding schedule advice - is 2.5 hour intervals too long?

7-week-old, breastfeeding primarily but taking expressed milk in bottles sometimes. Pediatrician said we could go 3 hours between feeds during the day, but baby seems hungry around 2.5-2.75 hours consistently. Should I just feed on demand or stick to a schedule? Wife says I'm overthinking it but I want to make sure we're not under-feeding him.