Is it durable? : There are two types of Halloween decor; those that are meant for parties and other such one-night events, and those that are meant for a longer shelf life. Metal, plastic, or heavy resin are you best bets for year-round home decor.
Will I use it? : If you are anything like me, the moment Halloween shopping strikes, you want everything. However, before you convince yourself that the eye-ball lights are a must, think for a moment about how you are planning on using them in your home. Do you already have an idea for a particular item before you came to the store? Can you think of a place to put something that may be more of an impulse buy? The great thing about this time of year is that we can find a spooky alternative to nearly every household item imaginable, but what good is a plastic grim reaper if he is just going to sit in a closet or in an attic while you wait for an opportunity to use him?
Also bear in mind that certain Halloween decorations can be used as Christmas decorations later on. I have multicolored skeleton lights for my tree and a black wreath with purple bats on it for my door, both bought the Halloween before Christmas last year.
eyeball ring I picked up last year
Will I wear it?: This pretty much goes with the "will I use it" question, but for clothes and jewelry. There are plenty of lovely things to be had during these months as far as Gothy fashion goes. However, you need to keep in mind how an item will look after the Holiday is over. Is it too Halloween specific? While there are many good reasons to wear skulls and bats all year round (unless Halloween imagery just isn't really your thing), but candy corn and ghost patterned things .... might be cheesy in a bad way.
Above all else, be creative! This is our opportunity to acquire things that will turn our environments into what we really want, so have fun and try not to go completely broke!