2 x 5 does not equal to 10

I have conducted various trainings and just like any other trainers, I ask questions to understand my audience better. One of the frequent questions is the years of experience in the participants' profession. It has happened to me so often that moving forward, I have decided not to take the participants' years of experience as answers but merely suggestions to be further verified. That's because most of the time, the years of working does not commensurate with the participants' level of understanding in their profession. For example, a guy may say he has worked in his industry for 10 years. After a few questions and also some role play, I realize that the person's experience is actually around 5 and not 10 years. I started to realize that the person actually has 5 years of experience but repeated twice (5 x 2). That's why his experience is only 5 years. If the person does not continue to improve himself, he will be 5 years x 3 in the next 5 years. So, when you say you have worked in your industry for 15 years, what do you actually mean? Is it 15 years where each year you improve yourself? Or 5 years x 3 which means you stop learning after the 5th year and you just repeat what you have learnt for year 6 to year 15? The key take-out: if you stop learning, your years of experience stops too. Happy learning!