Essentials multiplier

The essentials multiplier scales the baseline cost-of-living basket up or down by lifestyle. Frugal = 0.85×, balanced = 1.0×, comfortable = 1.15×, premium = 1.35×. The compression is intentional: you can cook at home and live with a roommate to cut essentials by 15%, but you can't realistically halve them without major lifestyle compromises.

Compare this to the leisure multiplier (0.4× to 2.5×), which has much more dynamic range. That's the empirical observation behind the model: most people's leisure spending is far more elastic than their essentials.

When stress-testing a budget, run the essentials multiplier downwards first. If a city is unaffordable at the frugal essentials level (×0.85), no amount of leisure-cutting will rescue it. The essentials line is the floor.