Perhaps a chef who has lots of experience with cookware might know when to or when not to replace a stainless pot. I use the pot for cooking great northern beans and it has been used for maybe 60 years. It is a 4 quart Revere Ware stainless steel sauce pot with a copper bottom. I use a 3M scouring pad to clean. After cooking there is some dark discoloration and I can feel residue there but the 3M pad gets it shiny clean. What prompts me to ask is that I have to clean it every time I cook the beans and that used not be the case so I thought I would ask before thinking about replacing it. The same pot on Amazon used is over 100 dollars since they are no longer made and it could be worse than mine so it behooves me to at least ask. 
I have a couple of those of the same vintage that are just fine. Sometimes the copper coating on the bottom wears away but these are generally long lasting quality cookware. Not sure about your cleaning assertion. I clean every pot and pan after using it, and as it is not a non-stick surface a little scrubbing with a scotch-brite, SOS or the like pad is not out of line at all, it will depend on what you cooked and what residue is left over. And yes any pot or pan will wear out, it just depends on how well they are made and how they are treated. A well-treated, quality, pot/pan could easily last a lifetime or two, or more... 