Most people grow up hearing the same rule: change your underwear every day. But dermatologists say the best answer isn’t one-size-fits-all. Your activity level, sweating, underwear style, and climate all affect how often you should switch to a fresh pair.

In low-activity situations—little movement and no sweating—some experts say changing every other day may be acceptable for certain people, especially men wearing looser styles like boxers.

Why Wearing Underwear Too Long Can Be a Problem
Wearing the same underwear repeatedly without washing can do more than feel uncomfortable. Experts warn it can raise the risk of:

Skin irritation and rashes
Friction-related inflammation
Worsening of conditions like eczema or psoriasis
Infections linked to trapped moisture and bacteria
Moisture and friction are a common bad combination. When sweat and heat get trapped, the skin becomes more vulnerable to irritation—and germs can multiply more easily.

Activity and Climate Change the Rules
Your underwear routine should shift depending on your day. You may need to change more than once a day if you:

Work out or do intense physical activity
Sweat heavily
Live in a hot and humid climate
Spend long hours in tight clothing
In these situations, changing more often helps reduce moisture buildup and keeps the area cleaner and drier.

Men vs. Women: Different Bodies, Different Risks

Men
Some dermatologists suggest that men may sometimes be able to wait up to 48 hours in very specific cases—minimal sweating, low activity, and breathable underwear (especially looser styles like boxers).
But men still face risks if underwear is worn too long, including:

Skin irritation
Jock itch (a fungal infection in the groin area)
Because of these risks, many experts still recommend changing at least once daily as the safest baseline.

Women
Women generally have less flexibility due to anatomy. The area is more vulnerable to bacteria moving and growing, especially with moisture and friction. Risks can include:

Yeast infections
Bacterial vaginosis
Skin irritation and rashes
Women may need to change more than once a day during:

Heavy menstrual flow
Significant discharge
Hot weather or heavy sweating
In these cases, changing more often can help with both comfort and hygiene.

What People Actually Do
Habits vary widely. Some people refuse to wear the same underwear beyond one day, while others occasionally go 24+ hours. Even if it feels normal, experts caution that longer wear can increase the chance of irritation or infection, especially when sweat, tight fabric, or humidity are involved.

A Practical Hygiene Guide (Simple Rules That Work)
Use these general guidelines:

Most people: change once a day
After heavy sweating/exercise: change as soon as possible
Hot/humid climate: consider changing more than once daily
If itching, discomfort, unusual odor, or unusual discharge occurs: change immediately and pay attention to symptoms
Prioritize clean, breathable fabrics and avoid re-wearing unwashed underwear
Bottom Line: Hygiene Should Match Your Body and Your Day
The “right” frequency depends on sweat, activity, underwear type, and climate. While some men may be fine going every other day in low-sweat situations, the safest overall advice is still: change your underwear at least once a day, and change more often when your body or conditions demand it.

Sources
“Doctor reveals how often you should change your underwear.” Unilad. Kit Roberts. January 9, 2024.
“Don’t bother changing your underwear every day- unless you’re a woman – top skin experts tell the Daily Mail.” Daily Mail. Emily Joshu. January 2024.
“How often should you change your underwear? The answer may surprise you.” NY Post.
Tracy Swartz. January 8, 2024.