I don't know if this necessarily means you should feed every day... just that you should supplement every time you feed.

Many people overfeed their dendrobatids and a lot of the frogs in the hobby are in fact obese. A day or two off here and there is more like what they would experience in the wild and honestly would probably trigger a stronger feeding response when flies are added. This means the frog will probably eat more flies immediately when they have lots of supplements still present.