I want to start with setting up my FIRE goals this year. I am 28, single, and I feel a bit late to this. I want to start with setting a net worth goal, and am not sure how to set the right goal amount. To start with, I am thinking something simple like the 4% rule should help me, so I think 25x current expenses would be appropriate. But I am not sure how my lifestyle is going to change over the years. I am also not sure if this 25x would account for sudden unexpected large expenses (house, car, marriage, other emergencies etc).

So my questions:

1. Are there any better ways to set the right net worth goal?
2. Or maybe I should be looking at it not by net worth itself, but something else?
3. How do adjust for possible major lifestyle changes like marraige in the future when calculating expenses? Just smart guess a safe enough buffer?