A better metric I like to use: how many extra years of work before retiring will this large expense cost me? (Admittedly: this does not work the same for housin

A better metric I like to use: how many extra years of work before retiring will this large expense cost me? (Admittedly: this does not work the same for housing for lots of obvious reasons). An example: a friend of mine is renovating the exterior of his house for $100,000. He plans to live there until he dies (it's a lovely house), so he'll never see that money again. He'll just have a nicer house. My alternative option for him: retire 4 years early instead. If you invest $1 now, you can expect it to double in about 14 years, give or take. So since he has more than 14 years left until retirement, that $100,000 would be $200,000. If he plans to live off $50,000/year, then he's giving up 4 years of retirement for the sake of his house looking nicer. If he plans on living off $30,000, then it's nearly 7 years early retirement. It's not exact math, but it's a good metric to put things in perspective.