Jenlovesmakeupp makes a good point, if your hair gets to the extent where the oil is in abundance, leaving it won't do you any good.
The key things to keep in mind are proper cleansing and using the right products. Try looking for sulfate free products as sulfates can dry out hair by stripping healthy oils from hair, making your body want to reproduce and regenerate oil at a quicker degree to replace what its missing.
Carol's Daughter makes a rosemary and mint clarifying shampoo that works well to remove the necessary oils, but also condition strands to be sure they're healthy.
In terms of dry shampoo, various brands like Oscar Blandi, Alterna, TIGI Rockaholic, Psssst, to John Freida make types. Depending on your hair color, some dry shampoos might leave a pale, white cast on hair if used in abundance. Try looking for ones specified as colorless or for dark hair if your hair is brown/black. Look up reviews online if you're ever unsure if a product may or may not leave a cast. These products can help to absorb excess oil, freshen up the look of roots, and even help add volume to styles by providing that "needed" buildup in hair.
Even though studies suggest to wash hair every other day, greasy hair NEEDS to be washed every day. Their is no way of avoiding it unless you want to buy a dry shampoo to help controll the grease in between days.