The fields that identify the night
Artist, venue, city, and date. Without those, you cannot tell two academy shows apart. Support acts belong on the bill when you saw them, under the headliner, not as a second fake headline unless they played their own date.
Radar’s gig page is that card: the listing if it is upcoming, your notes and photos if it is past, and the setlist when one exists.
The fields that make it yours
Rating, a short note, photos, and tagged friends. Those are optional and personal. They do not replace the date. A private diary can hold them without posting.
Upcoming gigs can sit on the same page shape before they happen, so the plan and the memory are not two apps.
Leave these off
Full ticket PDFs, every Story frame, and a copied Wikipedia biography. Door time can live in messages. The page should still make sense if you open it on a train in four years.
One gig, one night. Do not paste a whole tour routing into the notes.