Many salespeople find it 'culturally challenging' to say "no" or "I don't know". The problem is that they have to know about everything they sell, but you just have to know about what you want to buy, so you can research more deeply than they can. I spend much more time independently researching important purchases than I spend in the shop actually talking to salespeople and buying stuff. When I was working out how to set up my stimmie enclosure, I probably spent 15-20 hours researching (books and the web) and about 1 hour or so with the suppliers. And that was with the people at the suppliers being knowledgeable herps with whom I could test my ideas and listen to theirs!!! If I had been buying from a general (not herp specific) pet shop, it would have been 15 minutes of picking stuff off shelves and taking it to the checkout.