The enclosure itself is obviously included, and usually the basics of heating too, most often a heat mat or heat bulb. Beyond that, coverage varies a good deal between kits and suppliers. Some kits include a thermostat to regulate that heat source; others leave it as a separate purchase, which matters because an unregulated heat source is a genuine risk rather than a minor omission. Lighting, particularly UVB provision for species that need it, is included in some kits and entirely absent from others, often depending on whether the kit was designed with a specific species in mind or built as a generic starter option.
That said, there's a clear line between normal settling-in behaviour and something that needs attention. Prolonged refusal to eat beyond what's typical for the species, laboured breathing, unusual discharge, obvious injury, or any behaviour that seems more than ordinarily distressed are reasons to contact a vet experienced with reptiles straightaway, rather than waiting to see if it resolves on its own.
Enclosure space is the second consideration, and it's one that catches a lot of new keepers out. Many species sold small as juveniles need considerably more room as adults, and an enclosure that felt generous at first can become cramped within a year or two. Researching the adult size of a species, and the enclosure dimensions that go with it, before bringing the animal home avoids the costly cycle of upgrading tanks every few months.
Temperature and humidity checks matter more in these first 48 hours than at almost any other point, since this is when a keeper finds out whether the vivarium set up before the animal's arrival is actually holding steady under real conditions. Checking thermostat readings against a separate thermometer, ideally at both the warm and cool ends of the enclosure, confirms the setup is doing what it's meant to before the animal has been in it long enough for a problem to become serious.
More information is available at reptile keeper supplies.
Most
NRC Reptile Centre substrates are sold as general-purpose products, suitable in theory for a wide range of species with only minor adjustments. The ProRep Beardie Life range takes a different approach, building a substrate and accessory system around a single species, the bearded dragon, rather than adapting a generic mix to fit.