First, like any other living things, these are individuals. Some might say three times a
week is a lot.
Some may take to handling; others may never take to it. We can try to encourage, but in the end—unless it's necessary, like a vet visit—the decision whether to be "handled" or not should be up to them.
IMO, 30-45 minutes is about 10X too long/much. Only as long as is absolutely necessary to accomplish what is absolutely necessary. As I said above...
Beardies can & will take daily handling—or time out from their enclosures—for long-ish periods of time, and opinions will differ on that.
What kind of "things"? Apart from live plants, proper lighting, plenty of branches/dowels/sticks to get around on, and a decent feeder, chameleons don't need anything else. Aesthetic accoutrements are for humans—they are wasted on chameleons.
Crickets from any pet store are about the same; they should all be gut loaded, and there's always a (small) chance of parasites. Regular fecal screenings are a good idea for any/all reptiles.
When your vet appt. comes around, be sure to take a
fresh (less than 24 hrs. old) fecal sample with you. As to what you should know, read a few of these articles:
https://www.google.com/search?client=firefox-b-1-d&q=first+visit+to+a+herp+vet