There seems to be a lot of conflicting opinion on how much money you'll need in retirement in comparison to what you may need today. Is it 80%, or 50%, or even 100% because you're going to do all that world traveling you've always wanted to do?

Personal finance columnist Scott Burns suggests that a couple in retirement can live off of 50% less than a younger couple living in the same neighborhood.

How so?

Well, first off, kids. They cost a lot, which most parents have noticed.

Then there's saving for retirement. If you're retired, you're done saving--you've moved on to the spending. But if you're younger, you have to fund your retirement plan (or at least you should), so you're still paying out a chunk of your income to save for later.

The retired couple has no employment tax, but does get Social Security income (which is not taxed unless hitting a certain level).

And, of course, there is housing. If they've played their cards right, the retired couple has either paid off their mortgage, or they've downsized from a previous larger home and have no mortgage to deal with.

So retirement might be cheaper than you'd think. (Of course if you want to spend your winters in Hawaii and your summers cruising nationwide in the Winnebago, you might need to add a few bucks to the thoughts above.)