I'm pretty sure I've asked a similar question about this before but I don't think I ever got an exact answer. I have this supplement to dust crickets with:
Amazon.com: Reptivite 8oz: Pet Supplies
This has calcium and a multi-vitamin all rolled into one. I know vitamin supplements don't need to be used as often as calcium so I'm wondering if I should be using this as often as I am. I feed about a dozen med-large crickets a week for my 2" WTF and I dust at about every other feeding. Is this too often. Is vitamin toxicity at all a possibility? I spread out his feedings throughout the week so he gets 3 in a bowl about every other day and then on his "off days" I put one undusted cricket directly into the terrarium for him to hunt. So he gets 3 dusted crickets three times a week.

Another question I have is about Dubia Roaches. I'm going to an expo in a couple weeks and plan on buying a bunch of roaches since mine are HUGE and not breeding because I don't have very many. I know roaches are more nutritious so do I need to dust them as often or at all? And I'm not entirely sure how many roaches a week he could eat?