This was my first time and it was AMAZING. I can move pretty quickly and I'm looking only for specific things. That said, it legitimately took me 7 hours of walking the first day (Tuesday) and 6 hours of walking the second (Wednesday) to cover the entire show. A total of 40,865 steps according to my phone.
Aside from trying to see the Hermitage in St Petersburg in one day (I couldn't) I don't know of anything else I haven't been able to see in one day, including Disneyland, etc. Not to mention, this was all old car parts, so it blew everything else away!
Not only that, but I got to pick up some great parts for my cars. Just fantastic!