Forget the written hype of how many inches of water a plant needs per week. Every house, every garden and most soils are different. Learn how to let your plant tell you when it needs water. In the AM hours if your plant is beginning to droop, not wilt, but look droopy, it is time to water. When you water, water SLOOOWLY and COMPLETELY. The best way is to water houseplants from the bottom up but many of the plants are too big to do this. All of the soil must receive adequate water because the plants feeder roots are interspersed throughout the container of soil. If the plant is an outdoor plant the same thing applies. But if the plant droops and/or wilts in the heat of the afternoon it does not need watering, it is just slowing its transpiration process. Just remember that you cannot give a plant too much water but you can and will kill a plant by watering too often. It is much better to let a plant get really thirsty than it is to keep the soil wet. Very few plants like wet soil, they like damp or moist soil.