Interesting timing on this question. I'll be 54 in two months, and DW is 55. This weekend we went to a coffee shop with wi-fi access, and filled in some retirement worksheets at a couple different sites. To our surprise, we'll be able to comfortably retire next June when I turn 55! In fact, we've got enough right now, but in order to get full benefits I'm going to hang in there for 14 more months.
Our house has been paid off for a few years, and we really have no bills to speak of (except for DVC dues). We both worked our whole lives, and put the maximum into our 401(k) plans. We also never touched that money. The key is to start early if you can, and let time take it's course. Just play around with a spreadsheet a little; it's surprising how savings can compound.
Our situtation was a little unusual in some ways. We had a kid at 18, and another two years later. So they've both been out on their own for a long time. The woman in the office next to me is 53, with kids that are 13, 16 and 18. Her situation is a lot different, and I like ours better. Heck, my oldest granddaughter is the same age as her son.
If you want to try to "what if" your situation, we found the calculators at
Yahoo Finance and
SmartMoney Magazine to be the most helpful.