Are you still nursing a leggy spider plant left over from college? Some people seem to have the magic touch, most of us don’t know when to call it. Healthy plants provide better air quality inside our homes, as well as beauty. But know when to say when. Here are our favorite tips.DON’T be afraid to throw out a house plant once it’s past its prime. Unless it’s a jade plant, a very well-tended bonsai, most indoor plants are not something you’ll pass along to the next generation unless you have that magic green thumb. Once a plant loses its shape or dries out, don’t bother trying to resurrect it. Dying plants aren’t pretty or helping with air quality. Check out the ASPCA’s printable list here. For more tips, see our articles here and here.DO go big: buy the largest house plants you can afford. You want to make a statement and have the plants to be a part of the room. Small plants in tiny pots can become messy clutter. A large palm or ficus can fill an awkward corner or create a canopy over a seating area. DO treat the plants like accessories. It’s easy to fall in love with them, but they require careful planning and attention to look right. A row of small snake plants or succulents in matching pots make a lovely architectural centerpiece on a dining table. In a corner, use three sizes of the same plant – one large, one medium and one small – for more impact. DO put smaller plants on pedestals to make them look taller or for a more dynamic grouping. DO your research - choose only plants that suit your house. Most of our houses are dry and don’t have great light because our windows are coated to protect from the sun. A lot of house plants like humidity, even a bathroom isn’t enough to keep some plants happy. And if you have pets, some plants are poisonous!