Hi.
Thanks for the replies. I'm sorry I forgot to paste in the answers to the questions; I'd done so in my first forum post on the site, and wasn't thinking when I posted this question. Here's the basic info about Teach.
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He's 3 years old.
I've had him for about three weeks.
He's about a foot long, but is missing roughly half his tail.
The enclosure is is a glass 55 gallon horizontal tank: 4' long, 21" high, 13" deep, with a 1/4" hardware cloth top.
The substrate is washed and screened play sand; I also screened it before adding it to the tank.
I am using a UVB lamp: the bulb is a new ExoTerra 150 desert UVB compact fluorescent. (It's 13 watts)
Teach can get to within 6-8 inches of the bulb.
I'm using a separate basking bulb. It's a 150 watt infrared ceramic heat emitter, made by All Living Things. It provides only heat, no light.
The basking spot is about 100 degrees F.
The cool side temp is about 72 degrees F.
I'm using a heat gun thermometer to test temperature gradient, moving it around inside the tank.
The ceramic bulb is the tank's only dedicated heat source.
I've been feeding Teach salads every day, about 20 large crickets 3x a week, and superworms as occasional treats. His greens were initially just romaine lettuce, then romaine and minced carrot, and a little spinach and bits of grape. This week, he's been eating prepackaged "spring mix" greens, and a little thawed mixed veggies (peas, green beans, corn, carrots). I've been careful not to give him very much carrot, spinach, or grape.
On cricket days, he gets fed twice: first greens, then crickets. He's gotten the crickets after he finishes the greens, or as much of them as it looks like he's going to eat initially. When he's not getting crickets, he gets his salad in the morning, and has whatever's left removed at night.
I gutload the crickets with Fluker's high-calcium cricket diet, but was given to understand the superworms are eating their substrate (wheat bran).
I use RepCal calcium with Vitamin D3 supplement a couple of times a week. No other supplements, since the cricket feed is supplemented; with calcium, among other nutrients.
He was initially pooping regularly every day, a few hours after he finished eating. That's changed, although he's still pooping pretty regularly.
I
bathe him at least once a week for 20 minutes at a time to ensure
hydration. Sometimes he gets another
bath to stimulate his bowels.
I don't mist him, or keep water in the tank anymore, but mist his salads or don't shake the water off when preparing them.
I haven't brought him to the vet or had a fecal check done.
He's the only dragon in the house.
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I understand that sand is a controversial substrate, and why. That was part of the reason I asked this question. I haven't made up my mind about whether or not I'm going to continue using it as a substrate, but if I do, it'll be an informed choice.
He seems to have changed his timing -- initially, he'd poop every day, a few hours after he'd eaten. Now, he seems to be going in the morning, before he's fed. He seems to be going, on average, every day, or every other day. Mostly, every day.
I appreciate the info about frequency, and dietary remedies. I'm less worried now that I know it's not an immediate cause for concern if he doesn't poop every day. He's eating well, is alert, and variably active and mellow, depending on the time of day and brightness of his surroundings. I will continue to pay very close attention to how frequently he's pooping as long as I keep him on sand. As I said, I haven't made a final decision about that yet, and will keep the alternatives in mind.
You both mentioned
bathing him more frequently. I'm using baths to make sure he stays
hydrated, since there's no water dish in his viv. A book I read said that since the vent's biological purpose is sex and excretion, it absorbs water slowly and inefficiently. The book suggested that if you wanted to use
bathing to ensure
hydration, it'd take at least 20 minutes at a time, once a week. I have no objection to
bathing him more often if he needs it, but in general, I'm trying to opt for husbandry that's as close as possible to the conditions beardies evolved in. It's a compromise, of course. But I'm guessing a desert lizard probably finds baths pretty darn freaky. He certainly scrambles madly enough every time his feet touch the water.
Given that he's pooping pretty regularly, and seems to dislike being bathed, what purpose is served by more frequent, shorter baths?
One more question about pooping: he seems to have established a pattern. Should I save my worries for if and when the pattern changes?
I answered your other question too. You should remove the sand. It can cause impaction and it isnt the best substrate. It also harbors bacteria. Better options are tiles, paper towels, newspaper, and reptile carpeting. Also you should be 
