If you are serving 30 people, then you would allow one egg per serving or if saving eggs, then you can get by with just 15 because most mayonnaise has eggs in it.
How Many Eggs In Potato Salad For 30 People?
It could be whatever you see fit....but you can check out "foodnetwork" and enter it in search
(potato salad)
(potato salad)
Might not more then 10 eggs.