I'm not there yet, and don't plan to get there. I'm generally a goof off, and a lot of folks think I act like a big kid, but not when it comes to money.
I have a separate bank account I defer part of my paycheck to. That is goof off money, I can spend that on anything and it won't cause me financial trouble. I also place funds I get from selling off my unwanted parts/ equipment there, so that goes toward my Bronco and not lost in my fuel tank or the grocery store. Most of it goes toward tools and Bronco parts, or any other thing I want but don't "need" to maintain my life.
When it comes time to make a purchase for the Bronco, if it's in that account, I can afford it. If it's not, I can't and have to wait. I actually got a lot more careful with my money once I started doing that, and held off buying little junk I didn't really need in favor of saving up for more expensive items. Right now I have enough in there it's looking feasible for me to consider replacing a lot of the body sheet metal.