Just as you change your socks on a daily basis, never wear the same shoes two days in a row. Your feet perspire as you walk, and the socks don't absorb it all. Let your shoes air out and completely dry a full day and night before putting them on again, wear them every other day instead of every day, and they'll last about four times longer. (This practice also prevents athlete's foot and other such yuckies.)

P.S. I have some idea of what you go through to find shoes that fit; my feet are size 9-1/2 to 9-1/2W, depending on the shoe style. Shoes stores carry all the half sizes right up to size 9... and then most of them jump straight to 10. Some will carry an extremely limited selection of 9-1/2. So when I find a shoe that fits just right AND looks nice, I usually buy two pairs on the spot.