It is sometimes challenging to know how much cheese to serve at various occasions. If you have a cheesemonger close at hand, they will tell you how much cheese to serve depending on the purpose.
If you go to the grocery store, help might just be a bit more hard to get. In that case some advice may be appropriate.
At the end of a meal
Serve a maximum of three cheeses totalling 60 to 80 grams per person. I.e. 20 to 25 grams per cheese if you serve three cheeses. Slightly more og each if you serve fewer than three. If it is a light meal you may increase the portion to 80 – 100 grams. If you’re doing it the French way with dessert after the cheese, max 60 to 80 grams of cheese in any case.
Cheese party
If cheese is the main meal estimate about 300 grams per person. A little less if you also serve charcuterie.
Raclette
You need about 150 to 200 grams of cheese for a Raclette in addition to the other stuff included in the meal.
Cheese fondue
There are numerous recipes around, check them out.