I have an All Clad stainless steel pot and I was cooking some soup In it. The timer went off to tell me to turn the heat off but I must have been daydreaming because I merely looked at the soup at that point and walked away from it again. Maybe about 15 minutes after that I noticed a strange smell and I realized I had kept the fire burning. There had been only a couple of cups of water to begin with so that was all burned off by now and the noodles were burning at the bottom of the pot.  I was fortunately able to clean about 99% of the residue and debris off of it, thanks to some baking soda, vinegar, salt, and a lot of elbow grease. My concern is if I should still use the pot. Most of the Internet tells me it should still be fine and it was only 15 minutes and not an hour or anything. However, I'm a bit concerned because I stupidly had a similar incident a few years ago. At that time, I was boiling a pot of water and left it for 2 hours. (I know, bad). Though I tried to salvage that pot, the steel inside was definitely bubbling and buckling and when I tried to use it a few more times after that, it was making very unsettling, and very loud, snapping noises.  Speaking to All Clad confirmed that the heat that long in the empty pot separated the layers inside (hence the very visible bubbling) and it was time to retire the pot. Though this situation is definitely different in that it was only over boiled for 15 minutes and there was still food inside this second pot, and I'm reluctant to throw away an expensive pot and it looks fine (though there’s some discoloration on the outside). However, I'm also reluctant to take a chance if perhaps there has been some similar layer separation inside due to the heat (that might be too slight to see), and if this could cause some danger. Thank you for any insight or thoughts! 
First, I think you should maybe consider making better use of kitchen timers. The way to test whether you've damaged the pot is:  Fill it around 2-3cm deep with water Turn on medium heat Do NOT walk away.  Instead, watch and listen to the pot as it heats up  If you've damaged the fit or bonding between the layers, you will hear pings and cracking noises as it heats up.  If not, you won't. Remember to turn it off as soon as you've done the test. 