Well, the very obvious difference between the made up $100k and $200k is that you can build a much bigger nest egg.<p>You're saying half your pay now, so lets say this would let you live off your savings for 2 years to try and make a start up.  Well, if you keep the same lifestyle than $200k gives you nearly 3 times as long (you're saving half now, so the extra $100k would all be savings, aside from the extra taxes).