I was doing the same thing Knight, what with the Zelda Wii U and 3DS XL and all the games I got for Christmas I'm sitting on a pile of points, but, I thought, why cash them in now when they can get me Platinum status next CN year. But then I was 30 coins short for this game case so I had to do a little more.
In addition to what Matt said about PINs expiring, watch out for Post Play Surveys sitting on your account which I believe will generally expire faster than PINs and you'll miss out on 10 coins per survey for those.
I've been with CN since the beginning and I can tell you that things worth buying, like the gold wii nunchuk for instance, used to pop up like once or twice a year maybe, but to me it seems like since toward the end of last year there's been new stuff I like popping up every few weeks or so. Who knows if that trend will continue, but it does seem like they're kinda trying harder. There was the ALBW poster set, the 3DS XL charging cradle, the Luigi statue you mentioned, and now this game case. I wouldn't hold your breath for a Zelda statue or anything.
Any advice I could give you would be hit or miss...I went for this game case and now have 20 coins in my account, and I'm gonna just wait till July for Platinum Status to reset before registering more PINs (none of which are old enough to worry about expiring). If something nice comes out between now and then I'll just have to buy it second hand. My strategy here is just to hope that 2015's elite status reward is as cool as the Majora's Mask soundtrack they had last year. Trouble is you just never know, and my strategy could be all wrong. Between now and July they could come out with another thing that sells out in a day and resells on eBay for $75. And 2015's Elite Status reward might be a crappy set of pencils or something, and then I would be regretting not spending my points on the $75 thing instead. It's a crapshoot.
