Insulating your attic space thoroughly is one aspect of your home you should constantly monitor/maintain. Insulation does a number of things, but perhaps most importantly it prevents gradual damage from happening to the living space of your house.
There are two important concepts when it comes to insulation. The first is the amount of heat that comes into and stays within the home. The other is the amount of moisture your home experiences in a given year. Insulation is a sealant or barrier that slows down the amount of heat loss into the attic/exterior of the home and prevents water vapor from seeping in and eroding the home's sheetrock.
As you can imagine, there are a number of different types of insulation. Below, is a chart of the most common insulation types. Take a look at the chat to help determine which kind insulation is present within your home.