We have continually refined our detailed budget process since the day we decided to pursue financial independence and early retirement (FIRE wasn't a word then). That was in 1992, some 31 years ago. We are very sure of our income and construct the outgo accordingly. We even continue to save--specifically for possible exchange rate surprises and any (exceedingly rare) cuts in dividends. We budget our dividend income on last year's dividends, to allow for a completely flat year. We have been lucky so far always to have had year over year dividend increases that exceed inflation.
We budget for our "needs" and our "wants" each year (including a contingency line for the inevitable knee jerk "gotta have it." Thus, when we spend on a "want"--travel, small, fun purchases, etc.--we always know that we have the money (up to the limits we have budgeted). For example, we budget 8% of our income on travel, which we use to its max. We never worry about it when travelling. Same for eating out, and so on.
We budget income (95% which comes from US-based dollar assets) on 0.88 USD to 1.0 CHF (Swiss franc) and generally have a year-end surplus from the actual (higher) rates that we get. I track the USD/CHF pair assiduously and move money to Switzerland at what I believe to be the most attractive moments.
We focus our disposable income (such as it is) on things like experiences, gifts to charitable causes, and helping relatives where we can, instead of toys, like new cars, second homes, etc. Not that we could ever afford even a first home here in Switzerland. We rent. And we own a small 2008 Hyundai "city car," which allows us local travel. Otherwise we use trains and occasionally take a flight. We are pretty much done with buying things.
That said, art is my weak spot. If there is any primary knee-jerk purchase this is it. But notice it is "art" with a lower case "a."
-BB
P.S. Oh, another weak spot is audiophile equipment. My wife is even on board with this "hobby" of pursuing the impossible.