I see over and over irons that have pitted, rusted and damaged faces usually within the sweet spot of the face of the iron.
Fellow golfers always ask me after I play 200 + rounds year round how my 714 AP2 and 714 MB plus my Vokey wedge faces look absolutely great compared to their faces that are worn and quit frankly abused.
My only answer is daily maintenance, your clubs usually cost most more than a bi-weekly salary. And those people say to themselves these have to be quality clubs that will last a lifetime. I'm 48, but in my 40+ yrs of golfing that is a false hood. Especially when you are talking forged irons. What I witness from others on the first tee is that their clubs are as dirty or more from the day before when we teed it up again on the first tee. Clubs are your tools to the game, they can make you a hero or zero. And if proper maintenance is not performed daily then those high dollar clubs will soon look like second hand clubs.
You have to be committed to maintenance to your clubs after each round of golf.
I have never failed to take dish soap and a toothbrush and cleaned every club to include my putter and towel dried and put them in my bag for tomorrow's game. It takes all of 5-10mins to do this.
What most don't realize is all golf courses use fertilizers, insecticides and many other chemicals to promote healthy golf course. It's that chemicals that at impact between ball and club the you trap those chemicals into the club. And if you are one that doesn't perform maintenance after each round are at fault to club face breakdown. These chemicals breakdown the club faces coating and grooves eating away at them overnight and day after day. Sooner than later you start to witness discoloration and damage.
I buy new clubs about every 4 yrs or when the buying bug eats at me, and when it comes time to sale my old set, I can say to the buyer the condition is great and no club face damage cause I wash all my clubs after each round. A practice every golfer should commit to. Clubs are not cheap in this day and age, so why treat them as if you can just buy new sets each month. Make them last, shine like new and make a big buck when you want to sell for a new set in years later.