McArdle encourages thriftiness:
If you're not saving enough–and you know who you are–don't decide today that you're going to save 15%, and then forget about it tomorrow when you realize how daunting a task that will be. Instead, try this: divert an extra 5% of your income into a 401(k), IRA, or other tax-advantaged savings plan. If your 401(k) is stuffed but you don't have much of an emergency fund–or if, for some reason, you don't qualify for tax-advantaged savings–have 7% of every paycheck diverted to a bank account which isn't linked to your other accounts. It's a slow week at work, the perfect time to fuss with HR paperwork.
Follow-up on where to save here.