The best areas of a house for green board are those that experience regular, moderate humidity (like kitchens or bathrooms except for the bath/shower enclosure). In these areas, you can expect green board to hold up better and last longer than standard drywall.
Green board isn’t a great fit for saunas, indoor pools, shower enclosures, or any other environment where you can expect high levels of humidity around the clock, though. In these cases, you’d be better off using cement board which is waterproof and intended for use in truly wet – not just damp – environments.
Green board is not more fire resistant than standard drywall, so if you’re looking for a board for hot environments or fire-risk areas, you should consider Type X drywall rather than green board.