I've taken the same approach, and this month some of my guilt-free spend went to a nice burr coffee grinder to replace my old blade one. But I'm not going to try to calculate the amortized joy per $ or long-term savings I'll get out of it, I just love brewing coffee, this makes it better, and I could afford it.
In fact, I think no matter what your budget is like, it's important to have at least some "doesn't have to be justified" budget set aside, even if it's just $5 a month. If your monthly "doesn't have to be justified" budget is $5, and you decide to blow that $5 on an expensive coffee every month, that's perfectly OK and you shouldn't feel guilty.
And that doesn't preclude you from getting a good deal either. That doesn't mean you should spend days shopping around for a few dollars off every purchase, but "voting with your wallet" is always worth doing.
Yes, I am exaggerating a bit, but I think you missed the point.
I buy 8 pants for 3 euro each simply because they look fantastic on me. If it was a [new] clothing store I wouldn't buy 8 but I'd spend 100 euro on 5 of them and at most 50 for the other 3 if I ran into them there. I just didn't put myself in a [new] clothing store type of situation. I prefer to expose myself to (usually not very nice) second hand clothing at some interval. Sometimes they have something nice. Parts missing I buy new.
I see some wonderful old leather chairs too, the best one was sold regrettably. I also consider buying a really heavy suitcase massage table that I absolutely do not need but it looked really awesome, was in mint condition and was absurdly cheap. A fun day.
Clothing stores nowadays strike me as if everyone is going to a funeral. By comparison its a depressing experience but sometimes you have to. I wouldn't be able to sell those cloths at those prices, I'm paying for their ability to sell me things. (fool me)
Often it's cheaper given the bigger picture just to buy a new one, though. But, finding some old tech t-shirt in a thrift store is fun!
I definitely don't buy new vehicles.
That's exactly what I did: Started a small spreadsheet to work out how long it would take to pay off a $400 espresso maker. Turned out I would make my money back within a year.
Then there's the added bonus that I now own a decent espresso maker which has been great for making guests coffee/showing off. I also get to choose the beans and milk which means that if I wanted to, I could substantially lower the price of my self-made cup of coffee if I was ok with lower quality beans/milk (turns out that I am not ok with that, so no savings there :().
Their approach is more like a performance engineer. You look at the biggest costs first and reduce it down. I.e. Ask for a raise, refinance your place, find a cheaper place to rent, etc.
When you get down to the coffee you would be faced with: is it cheaper to make good quality coffee, or am I paying for the experience?
Personally I tend to view these re-occurring costs and I try to look at a way I can amortize them over a longer period of time. It's easier to justify the cost of a 200+$ espresso maker if I'm really that big of a fan and already have a defined habbit.