It’s worth noting that there’s no helmet requirement for the IDE on the Friday. If you’re not yet signed up for the DE over the weekend, and you end up not getting in, then you won’t need a helmet.
There’s a thread here somewhere about the 2015 rated helmets coming out in October. If you buy one before then, it’ll be a 2010 rated helmet and only good for 5 years. If you’re going to use it often, then it won’t matter as replacing it in 5 years won’t be an issue. If you don’t use it often though, then you’ll want a 2015 one if you have the option.
I’m on the waitlist for the August DE so I’m holding off on buying a helmet until I find out whether I’m in or not. If I get in, then I’ll buy a 2010 one. If I don’t, I’ll wait until October and get a 2015 helmet for next year.