There are four stages of COPD, though the definitions vary, depending on who's doing the talking. The most universal staging is the GOLD, which includes spirometry and PFT results, number of exacerbations experienced and level of functioning. The stages are usually used by pulmonologists and PCPs in determining which types of meds to recommend for people in each stage. That's very helpful, especially if you're dealing with a PCP who isn't that familiar with COPD and the medications available and being developed. Knowing where you are in the general progression of the disease is helpful to some people; others feel it's more important what you can do and how comfortable you are doing it. There are always outliers who don't fit in any of the quadrants very well, and that can cause concern among people who want things very clear; COPD is often very fuzzy around the edges.

Do ask questions and continue to ask questions, but don't be surprised if the answer is "we don't know yet". There's way more about COPD that we don't know than what we do know, so if someone's giving you a lot of "this is absolutely the way it is" kinds of answers, be skeptical.

Guess I'm lucky. Haven't had any of those as yet, at least not that I am aware of.

I am more inclined to go with the other answer too. There is a lot of Gaslighting about medical conditions when so many using the "one size fits all" approach. They forget that every Body is different. Covid gave the "experts" another way to think about how the pulmonary system actually works and some good research out of that madness is being used already to help US more. Humble is the word here.

My Doc is very experienced in Respiratory conditions and we met at my bedside during a hospital event. He didn't talk about stage(s) but didn't expect me to figure it out either. He is very knowledgeable about how our medicines and treatments work too. Since my primary doc always orders blood lab before my visits, the Pulmonologist reviews those too - even before I ask about the numbers. That is one key to staying on the UP side.

This site actually gives a pretty good
explanation about Stages and Treatments without getting bogged down in the details. Click on Resourcesat the top and scroll down to the Learn More section to find it.

My Dr. does not believe in the gold standards as in stages. He uses a newer A,B.C type grading system. Has more to do with how may times you have flare ups or exacerbations.