If its anything like mine yours will give you the lowest and highest temp recording so needs to be left on. They hardly use any battery so its fine left on :-)
1.0.0 Cyrus - Amel het Anery ph Hypo - CURRENTLY AWOL 0.1.0 Diamond - Avalanche ph Charcoal, Hypo 1.0.0 Garland - Bloodred het Hypo 1.0.0 Pinball - Carolina 0.1.0 Casey - Hypo Lavender Stripe het Amel 0.0.1 - No Name Yet - Crested Gecko