I don’t know that constant calculation is necessary. Good habits are good habits. You have to calculate a budget, but once you have it, all you have to do is stick to it. You know whether or not you can afford a more expensive apartment, so if you can’t, you know better than to move unless you must, no big calculation required unless your salary shoots up. The general advice for asset portfolios is to check in once a year and rebalance at that point, if necessary. No constant calculations there.
While it helps to do things in advance that save you money (pack a lunch, buy plane tickets in advance), those things require some planning, but they’re more good habits than things you have to really think hard about because they should be second nature once you realize you’re going on a trip or going to work the next day. Small changes like refilling water before Penn Station and buying wifi before going to the airport will save money, but only a few dollars here and there. Real savings comes from making an adequate salary for your needs, creating a budget that allows for those needs, and sticking to it. In other words, unless a water bottle and wifi puts you over your budget, why worry?