There are some sur­pris­ing rea­sons to rotate your footwear. Any­one who walks, runs, or hikes on a dai­ly basis should con­sid­er adding a few more pairs of shoes to their gear clos­et for impor­tant health-ori­ent­ed rea­sons. Take a look at the ben­e­fits of this invest­ment, and then decide for yourself.

1. Adap­tion hypothesis
The break-in peri­od for new shoes has been great­ly reduced by mod­ern mate­ri­als for shoe man­u­fac­tur­ing. Today’s shoes are designed for greater com­fort and breatha­bil­i­ty right out of the box. All ath­let­ic or sports shoes come off a man­u­fac­tur­ing line, and your feet need a chance to adapt to them (and vice ver­sa). Many shoes need time to release the odors that remain from the man­u­fac­tur­ing process (which is why shoes that have been sit­ting in a closed box reek of chem­i­cals). Rotat­ing a new­er pair with an old­er pair means less expo­sure to the stink and a reduced like­li­hood of devel­op­ing blis­ters and hot spots.

2. Extend the life of your shoes
Giv­ing your shoes a 24-hour recov­ery peri­od can extend their life and reduce con­cen­trat­ed wear. The great­est wear on shoes is from repeat­ed wear­ing. When your out­soles hit the ground dai­ly, they begin a pat­tern of wear in areas of the shoe that make con­tact, based on your gait, weight, and land­ing style. With every step you take, bio­me­chan­i­cal spe­cial­ists say, you are apply­ing upwards of 1.5 to 3 times of your body weight onto your feet—thus onto your shoes. By switch­ing to anoth­er pair the next day, you give your shoes a rest, allow­ing the foam in the mid­sole to decom­press and return to its orig­i­nal cush­ion­ing support.

3. Chal­lenge your feet and cor­rect deficiencies
Just like your upper body, the anato­my of your feet and legs can change from day to day, depend­ing on the stres­sors. After a long day of sit­ting, your feet might be unable to han­dle the forces gen­er­at­ed by the impact of run­ning, hik­ing, or even walk­ing. Buy a pair of shoes with more sup­port and sta­bil­i­ty for just those kind of days. Your feet and legs will appre­ci­ate some sup­port­ive align­ment to help you avoid fatigue and strain. Chang­ing or vary­ing foot load and re-dis­trib­ut­ing your weight with a com­plete­ly dif­fer­ent pair of shoes (like a low or zero drop shoe) will help you avoid stress­ing the plan­tar mus­cles of the feet, the Achilles ten­don, or ankles.

Along with dif­fer­ent shoe builds to address pres­sure points, fric­tion pat­terns, and force of impact, indi­vid­ual wear pat­terns impact the struc­tur­al integri­ty of shoes. It is best to have a vari­ety of shoes with vary­ing degrees of wear, cush­ion­ing, or sta­bil­i­ty. The uppers in an old­er pair of shoes, for exam­ple, may begin to stretch, which might be okay when your feet or legs feel fine, but may feel uncom­fort­able when you’ve been on your feet all day. By wear­ing dif­fer­ent shoes on dif­fer­ent days, you can avoid over­load­ing any one mus­cle, ten­don, bone, or lig­a­ment, and can even help strength­en others.

4. Keep them fresh and give them a rest
Rotat­ing shoes gives the ones you just wore a chance to thor­ough­ly dry out. This reduces the mold and fun­gus that can grow quick­ly in sweat-laden shoes. Long-dis­tance runs and hours-long hikes can pro­duce an immense of mois­ture in your shoes. Even­tu­al­ly, the sweat starts to break down the com­po­nents of your shoes, which can cause uneven wear in the uppers. Think of the uppers as the exoskele­ton or shell of your shoes that, along with laces, help hold and sta­bi­lize your feet.

Mois­ture can also lead to blis­ters or athlete’s foot. This fun­gi grows best in warm, wet places, such as the area between the toes and under­neath the balls of your feet. You typ­i­cal­ly catch it through direct con­tact with an infect­ed per­son, or by touch­ing sur­faces con­t­a­m­i­nat­ed with it. But ath­lete’s foot still needs the right envi­ron­ment to flour­ish. If you alter­nate the shoes you wear to every oth­er (or even every three days) you’ll thwart the growth of this fun­gus by giv­ing your shoes a chance to com­plete­ly dry out.