I just finished Money: Master the Game by Tony Robbins. Great book! 

One part that really hit me in the book was the long-term opportunity cost of "little" splurges like regularly hitting Starbucks or eating out. Relatively small monthly expenses may not seem like a lot of money, but they can represent a huge opportunity cost from the standpoint of retirement savings.  

For example, let's assume a guy named Joe spends just $5 every morning at Starbucks. Assuming 30 days in the month (to keep it simple), that adds up to $150 a month spent on coffee.   

What if Joe trimmed his Starbucks habit back to a max of $50/month and faithfully invested the $100 savings in his IRA? Assuming just a 5% rate of return on the money, this is what his former Starbucks money would turn into decades down the line:

• 20 years: $41,103.37
• 30 years: $83,225.86
• 40 years: $152,602.02

Wow. Assuming Joe is in his 20s or 30s, he could potentially add well over $100K to his retirement net worth simply by trimming back his Starbucks habit. 

Robbins makes the point that there's nothing wrong with spending money on things you enjoy, but keep it within reason. It's important to remember the long-term cost of overspending on little indulgences. 

Even if you can't give up the Starbucks or eating out habit, it's probably worth it to see if you can get a better deal on your cable package, car insurance, cell phone plan, etc., then invest the difference into your retirement savings. As you can see (and as Robbins points out), a little discipline today can go a long ways toward a better future in retirement.