I've never done SYC (although I haven't purchased anything but a pair of trousers in the past month, yay?) but to me it's similar to my weight loss commitments.
When confronted with something I know I shouldn't eat (that will satisfy only momentarily), I ask myself the question "is this thing more important than my long term goal?"
Ask yourself why you're really doing SYC, and everytime you're tempted to buy just ask yourself if that item is worth more than your reasons for SYCing.
Nonstop splurging has made it more difficult for me to go visit my family halfway across the country, so whenever I want to buy something that is a splurge vs. purposeful, I ask if that item is more important than getting to see my family.
Of course no item is more important than family, but you know what I mean. This is why I have wish lists and figure out wardrobe holes before I'm "allowed" to shop. I don't do casual shopping or internet shopping anymore either.
