It depends. If it meets a few "requirements" Before I'll make the purchase I ask:
1) Will I use it enough to warrant the price?
2) Can nothing that I own substitute it?
3) Is this a recipe I plan on making again?

It depends. I used to have a cheesecake pan, but recall only having made one cheesecake my entire life!

Yes. I have a springform pan, a tart pan , several different shapes and sizes of casserole dishes, a variety of ramekins, cookie sheets, large muffin pans, 4 ounce cupcake pans, jelly roll pans, assorted cake pans and Pyrex pans. Only thing I've never bought is a pie pan for myself, bought about 4 for my sister's house but they eat and make pies frequently. Luckily my mom taught me to buy things that stack into other things so all of those pans are a cinch to store. And I do use them all at least 3 times a year. All of my pans are seasoned so I know the results I'll get as far as appearance and doneness when I use them. Some foods cannot be faked in other pans like an angel food cake cannot properly be made in a springform pan or normal cake pan. Heck I think you'd have an enormous mess on your hands if you tried to make one in a normal cake pan.

So permanent equipment I'll buy while decorating equipment I don't. So I don't have a cake turntable or piping bags but I do have cake spatulas and parchment paper.

I'm with Sy.

most of the time i'll do it. there aren't too many recipes that require things that i don't already have - so if there is something i'm missing - i kind of like to get it cause it's new.

I saw the coolest bundt cake pan that looked like a castle:
http://www.amazon.com/Nordic-Ware-Cast-Castle-Bundt/dp/B000F5M044

My husband LOVES castles, and anything medieval, and I almost bought it, but then I thought.. for how long is that going to be fun? Two times, or three?

I ended up making a sheet cake and cutting it up and reassembling it in the shape of an a little less intricate 3D castle

I'm with Syako

I'm with Syako on this as well. The only thing that I've purchased that comes to mind is a set of Springform pans, because I love to make cheesecake. Otherwise, I can usually find a reasonable substitute out of things I already own.

I'd totally buy it as long as the price isn't crazy and I felt there's a good chance I'd remake that recipe, or a similar one, in the future. (PS, your tart was AMAZING and well worth the pan's price IMO).

I'm with most everyone else. I'll buy something if I can't use anything else for it and if it's not too expensive. Every now and again I will buy something that I think we need but that's rare.

Other: I'll try to find what I need from a roommate/friend.

Two of my best purchases have been a springform pan originally to make an almond clementine cake and a madeline pan for my husband to make me madelines. Both high quality, made in Germany and France respectively, and hopefully will last a lifetime.

oh yes i do buy new bakeware esp if its for cakes/ tarts which most times require specific ones!

I'll just borrow from my mom she has everything!