If you're starting your blanket collection from scratch with a new horse, consider buying a system of matching clothes including a sheet, stable blanket and turnout sheet that will connect to each other. You'll be set for almost any situation.
Most of us, however, already have a collection of mismatched horse clothes, so all we need to do from there is fill in the gaps as needed.
Consider these wardrobe elements:
Stable sheet. Use one under the stable blanket. You can launder this regularly at home, so you can wash the heavier blanket less frequently and easily keep a clean layer on the horse's coat that will prevent bacteria from building up. If you have two, you can alternate them while one is being washed.
Stable blanket. A midweight blanket will suit most situations. Use two if your horse is clipped and living in a cold climate. Two midweights are more versatile than one heavyweight.
Turnout sheet. A sheet is lighter and more versatile than a turnout blanket. You can toss it over the stable blanket when the horse goes out, as opposed to removing the stable blanket in order to use a heavier turnout blanket. A turnout sheet can be used by itself in the spring and fall for turnout in muddy conditions to reduce grooming time.
Anti-sweat sheet. Cotton fishnet. When the horse gets sweaty while riding, he can dry off without getting chilled. It can be left on under the stable blanket, if necessary.
Cooler. Traditionally wool, but fleece works well, too, and is easier to clean and lighter to handle. Use over the anti-sweat sheet or by itself if the horse gets sweaty and steam is rising up from his coat in cool weather, so the sweat can evaporate and the horse won?t get chilled.
You may also want to add these:
Turnout blanket. Look for the thickness that will match your climate, if needed.
Heavyweight stable blanket. For particularly cold climates or horses that get overly cold.
Quarter sheet. Keeps the horse's back and rear end warm while exercising in cold conditions. If you want to cover the back while just walking in the ring, you can use your cooler.
Hood. For head and neck in very cold climates.
Slick liners. To prevent rubs and condition coats. A well-fitting, clean blanket shouldn't rub. Polar-fleece stable blankets, used by themselves, are particularly nice for conditioning coats but easily pick up bedding.