Take care of your feet, and they'll take care of you.
From "Prevention Magazine," by Maggie Spilner:
For many walking is an important part of weight loss.
If you're going to be a dedicated walker you need one primary piece of equipment--good walking shoes! Choose them with care.
Ideally, you should have two pairs so you can alternate them and let them dry out. This minimizes foot odor and the possibility of a fungus infection.
On the day of your purchase, record the date in your walking log, or even inside the shoe with a permanent marker.
Most shoes should be replaced every 500-700 miles. If you estimate your weekly mileage, you can predict when you'll need a new pair. Or you can keep a mileage log and track your accumlated miles on that pair of shoes.
You can look for sales, but don't skimp on the quality of your shoe. You want good cushioning and support. And you want to be sure your shoe fits. You should be able to press your finger down in front of your longest toe. (In other words, your toe should not be pressing up against the end of the shoe.) And if you hold a shoe up against the bottom of your foot, and your foot is wider than the shoe, it's too narrow for you. Ask for a wider width or a different brand.
Some women may be more comfortable in men's walking shoes if they have especially wide feet.
We prefer walking shoes to running shoes for walkers. They are built to help steady your foot through the heel-toe walking motion. But if you tend to suffer from painful feet and need extra cushioning, try a cross-trainer (a shoe designed for walking and running.)
There are many good brands out there. Try them all till you find the one that fits your foot the best, then stick with it!