Actually, Judah'sHuman is right about the kale, should only be fed with other staple greens. In case you haven't seen it, this site shows the daily staple foods in green ink:
http://www.beautifuldragons.503xtreme.com/Nutrition.html It's also a good idea to offer a variety of greens to keep there interest and would think that one green fed every single day, could get boring. I don't think any of us humans would want to eat the same thing every day.
Fresh greens should be put in their tanks daily as they do dry out very quickly because of the tank temp. Also, misting the greens just before you put them in the tank helps to hold the moisture in. I buy enough greens to last a wk and I cut it up on a Sunday, place in a large ziploc freezer bag, squeeze it to get all the air out and store it in the vegetable keeper. If any of the greens have any brown on or are starting to turn yellow or droopy, I remove those parts and don't even bother cutting them up, just toss them and only use the real fresh ones. Favorite greens here are collard, escarole, endive, mustard, and dandelions (when they are available) and I usually mix in a little kale, a little bit of swiss chard once in a while and add either a small amt of parsley, cilantro or snap peas on the top.