The part about matching a 15 year old part number is the real killer here. Here is the thing nobody talks about: serial plate photos are not just for returns, they are proof of what you actually found when you got there. I have had two calls where the customer swore the board was the original and someone had already swapped it with a used one from eBay. If I had not snapped that plate first, it turns into my word against theirs. The plate tells you the build date, which tells you if that part number even existed when the unit was made. A board from a newer rev in an older unit is a dead giveaway that somebody was in there before you. Takes ten seconds and it has saved me twice now.

I used to just pay whatever it rang up because arguing over a couple bucks felt like a waste of time. Then I caught a $6 difference on a thing of coffee and realized I'm basically donating money to a store that makes billions, so now I check the shelf tag before I even get to the register. They do have to honor the marked price in most states, but you gotta ask for a manager and sometimes show them a picture of the shelf tag.