Nowadays specialised pet shops offer a wide selection of terrariums which are usually made of silicone-sealed glass panes. They usually have sliding doors at the front. Small terrariums for invertebrates are also often available with trap door instead of sliding glass panes at the front. It’s hardly worth building your own terrarium anymore.
You need to consider the species-related requirements of your pet, its size and the intensity of its activity, when selecting the format, volume and technical equipment of your terrarium. The general rule is: the more space, the better! The technical equipment always needs to be adapted closely to the terrarium’s volume to prevent loss through overheating, should the control technology fail. The habitat needs to be designed with suitable decorative objects that the animals have enough opportunities to retreat, but some supervision and an ideal hygiene level can still be maintained.
For bottom dwellers the surface area is of course paramount, for tree dwellers the terrarium height. A strict classification into a couple of standardised terrarium types is not feasible because of the many different requirements and environmental adaptations of the animals, and also because the differences between the terrarium types are not fixed.