This is the one pan that has the ultimate potential to last a lifetime, which is more that I can say about most.

As long as you season and clean it right!

Seasoning a cast-iron skillet is a technique in itself.  Due to cast-iron skillets not coming home with a nonstick surface, one must season or coat the skillet with cooking oil and baking it in a 350 degrees oven for an hour.  Every time oil is heated up in the skillet it, this will reinforce the nonstick coating.

Cleaning a cast-iron skillet is a little trickier.  Pre-soaking this skillet will not help in the cleaning process.  Once you are done using a cast-iron skillet, make sure to rinse the pan with hot water immediately after cooking.  If you need to remove burned-on food, scrub with a mild abrasive, like coarse salt, and a nonmetal brush to preserve the nonstick surface.  Adding a few drops of mild dishwashing soap every once in a while is ok as well.  If the pan gets a sticky coating or develops rust over time, scrub it with steel wool and reseason it.  To prevent rust, dry the skillet thoroughly and lightly coat the cooking surface with cooking oil. Cover with a paper towel to protect it from dust.

Source