Which skillets / Fry Pans should I have?

DeBuyer Mineral B Element Iron Frypan, 12.6-Inch Round (32 cm)

Sizes:

• 8' or 20 cm: One egg; single grilled cheese sandwich.
• 10' or 24-26 cm:  Omelette; small servings of protein for two; garnish (vegetables) for two - four.
• 12' or 30/32 cm:  Everything else (long fish filets, for example).

Choose the skillets by the size of your pan's lids. I chose 20 and 24 cm because I had these pans size lids. Though, I miss the bigger skillet. I have doubts if I would choose the bigger size in Cast Steel Iron (De Buyer) or Stainless-Steel (All Clad, for example).

Someone gave a good tip:

Family of four:  I recommend one of each, maybe two 10" or 12", and please think about adding at least one non-reactive skillet (such as stainless) as well.   

A set like: 

• one 8", 
• two 10" (one reserved for eggs only), 1) stainless skillet;  2) cast iron (can be also 8', instead);
• one 12" a stainless "saute" with a helper handle; for chicken fryer, would be close to ideal.

You'll also need at least one lid in each size. 

I bought a 8' (20cm) Cast Steel Iron (I prefer this material than cast iron). I have a non-stick Tefal that is getting damaged. So, for now, I hope one is enough. My Tefal 10' is still fine. So, I need to buy a 12' and then checking if I have enough (3 and not 4 fry pans, because I will go by De Buyer collection).

Links:

• All Clad Stainless-Steel 12-Inch Fry Pan with Lid (30 cm)

• The 7 most essential kitchen Cookware