Many tarantulas have many different needs. Make sure you fully understand their nutrition, the temperature and humidity requirements that your specific tarantula needs.
Most tarantulas eat flies, crickets, small frogs, lizards, and mice, depending on the size and species of the tarantula.
Find out where your tarantula normally lives. Some tarantulas live in trees where height is more important than ground space.
If you have a tarantula that lives on the ground, then it is more important that the tarantula has room to walk. Its native climate will also dictate the ideal temperature and humidity levels that the species needs...
Find out more in this podcast.