4 ideas
Elizabeth Willard Thames and her husband Nate, both earning high professional salaries in Cambridge, Massachusetts, cut their spending hard, dropping eating out, cutting their own hair and relying on the library, and saved most of their income. The case shows how quickly early exit becomes possible when a high income meets a very low spending rate.
How fast a household can leave paid work depends on the gap between what it earns and what it spends, not on thrift alone. Frugality on two large salaries gives a much bigger gap than the same habits on a modest income. So a high-earning couple's timeline is evidence for what their income allowed, not a method anyone can repeat with the same result.
Treat each purchase as a vote for or against the life you say you want. Once a specific goal gives spending a purpose, cutting costs stops feeling like deprivation and becomes a way of buying something you value more. The discipline comes from how clear the goal is, not from willpower applied to each small choice.
An extreme lifestyle change only lasts in a marriage if both partners want the goal and help design it, rather than one enforcing rules on the other. Shared goals, regular talks about money and agreed reasons for each sacrifice turn frugality into a joint project instead of a source of resentment. On this reading, the partnership is the real engine of the plan, and the spreadsheet is secondary.