As mentioned, deciding what makes a tarantula happy is at best an academic exercise. I can tell you, however, that most ground-dwelling spiders, especially females, are pretty loath to leave their territory. Most wild tarantulas spend their entire lives within the same 10-foot radius of their burrows. (Males do wander to seek mates, but only at the end of their lives.) Add to this the fact that without a drag line, a tarantula would be largely incapable of finding its burrow again should it wander too far, and you’ve got yourself the ultimate home-body. My smaller spiders do wonderfully in standard 10-gallon aquariums. Larger ones appreciate the leg room of a 20 or 30 gallon.
I can’t say I can recommend building your own enclosure, since glass or plexi tanks are so cheap, easily cleaned, and well-suited to controlling temperature and humidity. They can also be purchased with locking lids- the best kind are the ones that have a sliding lid built into the top of the tank which can be secured with a peg. Regular screens can be easily pushed off by a determined spider, and then good luck finding him/her. Also, a fall of more than a few inches will seriously injure or kill most tarantulas. Ground-dwelling species are very clumsy.
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Indeed. 