Long trips are won or lost in the planning spreadsheet, but the spreadsheet does not need to be complicated.
Work out a daily target for food, beds and local transport, then double it for the first week while you calibrate — every destination has a real cost of living, and you will not know yours until you have spent it. After that, track spending weekly rather than daily; daily tracking becomes a chore nobody keeps up.
Book the big-ticket, hard-to-change items — flights, visas, a trekking permit — before you leave, and leave everything else loose. Overplanning a three-month trip wastes the exact flexibility that makes it worth taking three months in the first place.
Build in one splurge a month and one true rest week with no sightseeing at all; both keep budget trips from curdling into endurance tests. The cheapest way to see more of a place is usually to slow down, not speed up — fewer moves, fewer transport costs, fewer wasted travel days.
