Interesting post on Ben Pridmore’s blog:
"I've got to create that 10,000 image system for numbers. I don't think I'm ever going to get over 2000 with my current one, and scores way above 2500 are rapidly becoming the norm"
WEll, Josh, back to the library. You’ve only got 7000 more images to go. 
I’ve heard of parents using Baby Einstein CD’s with their toddlers. We need a Baby Pridmore CD to start them learning a 10,000 system in the crib. Imagine if as much time was spent on memory training as there is on teaching tennis. Baby Einsteins indeed!
One thing that Ben wrote in his post was that he usually struggles with recall. For some reason I thought that memorizing faster would make recall easier, but locigally I guess it wouldn’t.
I’ve considered 10,000 images in the past, but then decided against it. I’m not trying to win competitions–if I can eventually memorize a deck of cards in 40 to 50 seconds I will be very happy.
I’m still trying to figure out if the system makes that much difference. Is Wang Feng really using a 2-digit system with 100 images, or is that just a simplified explanation for the media? If he is using only 100 images, then maybe training is more important than the system.
Has Wang Feng ever told people what system he uses? (other than the YouTube videos which might not be his actual system)
I wonder how that system would be rehearsed. So Ben, for example, can do a deck of cards with his system in under 30 secords, right? So that’s about 26 images, give or take. So to get that that speed, at some point he had to be able to rehearse his system (i.e. go through the card to images mappings in his head) at a rate of more than 1 per second because he needs time to put them them in his journey, too.
Let’s say that before you can use a system, you need to be able to translate any peg in your head in under a second and if you can do that, you can start using the system. For a two-digit PAO, that’s 300 things, so you can rehearse your whole system in 5 minutes. A Ben card system with 2704 images maybe takes 45 minutes to an hour, depending on whether you need to go to the bathroom, breathe, etc. It’s likely harder to retain, so a fair amonut of practice would still need to be spent making sure you don’t forget your system. It’s doable for a semi-professional, I guess. Clearly some people manage it.
Now for 10,000 images, I don’t know. It would only be practical to rehearse part of the system each day. This isn’t a total disaster. For example, musicians learning new instruments don’t necessarily practice every scale every day, but they eventually get proficient in all of them.
Now for another thing. A frequent comment is that larger systems reduce repeats when memorizing longer sequences. This is obviously true and is usually cited as a benefit. However, with a large enough system, you wouldn’t hit all of your images in regular practice just with random digits, for example. With smaller systems your images will come up enough that regular reherasal of the system is less necessary. With a 10,000 image system, it’d be like, “hey I haven’t seen 7843 in a while. What is that again?” And there you are deriving it from first principles, phonetics, categories, whatever, which I’d think has to slow you down. But maybe someone using such a system would say, “no, no, no, you can just learn to derive them really fast!”
Maybe the experienced mnemonist eventually reaches a point where they conclude that they have reached a real limit in other areas and bigger chunks are the only option left, no matter how grim.