Just spent a week in Athens, here are my thoughts:

We stayed in Koukaki which was fairly centrally located but still a bit of a hike from the things we wanted to do. If I had to do it again, I’d stay somewhere near the university/north of Kolonaki as it was a little quieter and closer to the museums.

Buy sunscreen at the airport duty free shop on your way into town. It gets infinitely more expensive the closer you get to the beach.

My favorite restaurant was Kouvelos & Garden, you don’t need reservations but it doesn’t hurt to put them in via the website. You can indeed get bad Greek food in Greece, but this place was tops.

You don’t need to go to both Agistri and Aegina — both Aegina old town and Skala have fairly similar tourist experiences/things to buy. I would just go to Agistri as it was easier to navigate the whole island on e-bike, the beaches were less populated, and the beach chairs were a little nicer. If you’re worried about missing the pistachio stuff, I bought all the same products in Athens from the same brands that were sold on Aegina. You will need some kind of transportation on Aegina and taxis are a bit tough to come by, so that means renting a car or scooter.

If you have a chance to try Kaimaki/Mastica anything, do it.

The Plaka and surrounding shops are worth a walk through but yes, everything is priced at a premium. All the olive oils/vinegars/etc. can be found at local bio organic shops for half the price. It is a great place to get a 5 EU t-shirt, however.

Let me know if you have any questions!