I think a big part of it comes down to what you plan to do during retirement. Imagine if you inherited enough money to immediately retire if you wanted. What would you do with all that time? For me I'd probably continue to work, not in the job I'm currently in but doing something I really want to do. It'd be hard to fill in all that time with just leisure activities. I'd really need some fulfilling meaningful projects.
Alan Watts has a great talk about this that i've listened to many times:
Really? It would I agree! Sometimes I feel that way about being self employed. While I'm still on a strict budget I have to decide what I want to do each day. I think my retirement would be alittle more expensive, Because I would want to travel a lot. Although I also wouldn't mind working abroad for extra cash.