Short answer
Most kitchens use both. Aluminum heats quickly and evenly and is lighter, but it reacts with acidic foods and does not work on induction unless it has a magnetic base. Stainless steel is durable, non-reactive and easy to clean, but it conducts heat poorly on its own, so good stainless pans have an aluminum or copper core or base.
Aluminum is a common choice for fry pans, sheet pans and large stock pots, where even heat and low weight matter. Anodized aluminum has a hardened surface that reacts less with food.
Stainless or clad stainless suits sauces, braises and anything acidic, such as tomato or wine reductions, which can discolour in plain aluminum.
For induction, check that each pan is marked as induction-ready. A magnet that sticks firmly to the base is a quick test.
Updated · By Norpex