Sixty photos for a 60th. Thirty for a 30th. All on one sheet, printed and posted.
The presents people keep are the ones that took some thought. A poster of forty photos for a fortieth is one evening of going through the camera roll, and it ends up on a wall for years.
Photos go in the order they were taken, so it reads like a life: the blurry early ones, the haircuts, last summer. Add a title along the bottom — a name and a year is usually enough.