Important point to make.  We were told to try to break our web reporting program to look for bugs and we tried as hard as we could to find them, but in the end we could not have forseen all the stupid things people would do wrong, at least we made the list shorter of things we had to fix after deployment. IT people are the only ones living in the delusion that they know everything, but the truth is they need those that know nothing to test their wares and make them better. We really do both need each other.

Yes, indeed - once you launch a website or program, you discover that users do lots of things you don't expect. I think sometimes it's actual errors and bugs, but a lot of it is also that you envisage a certain pathway or logic to the way things will be done; and then the users think differently and so do things in a different order.

In puppetry this makes perfect sense because you may build something that does X, Y and Z, but then the puppeteer gets it and realises that it doesn't work that way for them - the puppeteer is X feet tall while the builder is shorter, so the puppet isn't quite as ergonomic to use as it might be, etc.

Like with all projects, you can be so busy trying to make something work that you miss a problem; so handing it over to someone else who hasn't worked on it will help you find the potential problems.

Yes, there is no substitution for actual practise with exact staging and puppets to find the bugs you never saw coming. We did 3 shows for a range of young ages so we did youngest to oldest shows so that if any problems came up with the youngest group first we could work them out before the older ones who would notice more. Added benefit was we would think of better lines or actions to add and we got better every show. Video taping a practise is very helpful to give you the audience perspective too.

That's a great idea - must remember that. And I agree with video taping. We did that a lot for shows after uni.

I think maybe why builders get a better idea of how the puppets work might be to do with the fact that while you're building them you're probably also doing a little bit of unintended improvised play.