Nearly every household has a rule about this and nearly every household made it up. Some things get washed far more than they need, which wears them out, and some things get washed almost never, which is worse.
Here is what the actual answer looks like, item by item, and why.
The principle underneath all of it
Two things decide how often something needs washing: how much skin contact it has, and how much it traps.
Direct skin contact means body oil, sweat, and skin cells transferring into the fiber. That is the main soil in household laundry and it is what causes yellowing, stiffness, and odour over time.
Trapping means the item holds moisture, which is what turns ordinary soil into a smell.
So an item worn against skin for a full day needs washing far more than a jacket worn over three other layers, regardless of how either one looks.
Every wear
Underwear, socks, and anything worn next to skin all day.
Activewear and anything worn while sweating. This one is not optional. Technical fabric holds body oil in a way cotton does not, and a single unwashed workout is what starts the smell that never quite leaves.
Swimwear, rinsed immediately and properly washed weekly.
Every two to three wears
Shirts and blouses worn against skin, in normal conditions. Sooner in heat.
Trousers and leggings worn against skin.
Pyjamas. People stretch these much further than they should, and pyjamas collect a full night of skin contact every time.
Bras. Every two or three wears, and rotate them rather than wearing one repeatedly. Elastane needs a rest day to recover its shape, which is the practical argument for owning several.
Weekly
Bath towels, used by one person and hung spread out to dry between uses. If it does not dry properly between uses, sooner.
Hand towels in a busy bathroom, more often.
Bath mats, weekly.
Every five to ten wears, or seasonally
Jeans, which are the most argued-about item in laundry. Washing them constantly fades and wears them fast, and never washing them lets body oil accumulate in the fiber where it breaks the cotton down. Every five to ten wears is a reasonable middle, cold and inside out. The freezer trick does not work: cold does not remove oil and it does not reliably kill anything.
Jumpers and sweatshirts worn over another layer.
Wool, which is naturally odour resistant and genuinely does not want frequent washing. Air it out between wears and wash it a few times a season.
Coats and jackets, once or twice a season plus at the end of the season before storage.
The things almost nobody washes often enough
This is the useful part of the list.
Pillows. Two or three times a year. Not the pillowcase, the pillow.
Duvet inserts and comforters. Two or three times a year.
Reusable shopping bags. Monthly, and immediately after anything leaks.
Bath mats. Included above and worth repeating, because they are damp for hours every day.
Pet bedding. Every one to two weeks, and it is frequently the source of a household smell nobody can locate.
Backpacks and gym bags. Seasonally at minimum.
Cushion covers and sofa throws. Seasonally.
Curtains. Twice a year, more in a kitchen or bathroom.
Oven gloves and cloth napkins. Far more often than they get.
What changes the interval
Adjust upward for heat and sweating, for skin conditions like eczema or acne where fabric contact matters, after any illness, for anyone working in a dusty or greasy environment, and for babies and small children.
Adjust downward for outer layers worn over other clothing, for wool, and for anything worn briefly.
The Long Beach adjustment
The climate here shifts several of these, and not in the direction people assume.
Mild temperatures mean less heavy sweating than an inland or humid city, so shirts and trousers genuinely stretch further here than they would in Houston.
What does not stretch is anything affected by salt air. Salt is hygroscopic, meaning it draws moisture from the air, so fabric carrying salt stays slightly damp and does not fully dry. Beach towels, swimwear, and anything worn near the water need washing promptly rather than being hung and reused, because they are not actually drying the way they appear to.
Sand is the other one, and it is mechanical rather than biological. Sand in fabric abrades it from the inside every time it moves, so a beach towel used twice without washing is being sanded. Shake everything out thoroughly before it comes home.
Where the intervals get easier
Most of the neglected items on that list are neglected for the same reason: they do not fit. Pillows, duvets, cushion covers, and pet bedding are bulky and absorbent, and a household drum cannot tumble them, so they get postponed indefinitely.
The machines at our self-service laundry on East 7th Street have the drum volume for those items to move freely, and the higher extraction means a pillow or duvet leaves the washer dry enough to finish in one dryer cycle rather than three.
Our machines and the store are cleaned daily, which is the same interval principle applied to the equipment.
Our wash-dry-fold service covers everyday laundry when the seasonal items and the weekly ones are competing for the same evening.
The short version
Skin contact and moisture trapping decide the interval, not how dirty something looks. Underwear, socks, and anything worn while sweating go every wear. Shirts, trousers, pyjamas, and bras go every two to three. Towels weekly. Jeans every five to ten wears, cold and inside out, since washing constantly wears them out and never washing lets oil break the cotton down. The items people genuinely neglect are pillows, duvets, reusable bags, bath mats, pet bedding, and curtains, mostly because they do not fit in a home machine. Near the coast, salt keeps fabric slightly damp and sand abrades it, so beach items need washing promptly rather than reusing.
WaveMAX Long Beach is at 601 E 7th Street, easy to reach from Long Beach and the surrounding area. For the bulky items that keep getting postponed, call us at (562) 269-0509.