At Wendy's the burgers are on the grill all day. They start on the hot part and move to the warm side. They get dipped in the grease if they are drying out. When they get too old they go into the chili. (there is a bucket next to the grill for that) Wendy isn't horrible if you get one right at the end of the lunch rush when they are fresh but between 2 and 4 they will be nasty most of the time. The chili is nothing but a white bucket full of old burgers and a couple of #10 cans of the secret sauce with beans in it.
Shakes at all of those places are just a bag of powder and ice water in a chiller machine that keeps them stirred up.
I can't even describe what that log of powdered mystery meat at Arby's looks like before they roast it.
Work in fast food a while and you get pretty selective about what you buy.
BTW fries are the highest profit item in a fast food joint. That is why they always push fries and want you to super size them. I spent a few months with the BK management folks and learned more than I wanted to know about it. Five of us did the T3 class to teach managers how to teach their folks about the new computer system and we had to know most of the financial aspects of a BK store. (circa mid
90s) I also did a similar thing at Wendy's when they rolled out the same basic system but we had Wendy's for years before that. We did the Arby's self order kiosks in the early 90s but they weren't popular and that program died. McD started it back up again a few years ago. Now they are working with IBM on an audio response drive through order system.