A turban that is washed properly retains both its color and shape for years. One that is washed incorrectly becomes thin, faded, and loses its elasticity within a few months. The difference comes down to three things: temperature, drying, and frequency.
How often
More often than you might think. A head covering sits directly against the skin all day and collects sweat and skin oils, just like a garment worn next to the body. If you wear it every day, every other day to every third day is reasonable, and more often in summer.
That is also why it is a good idea to have at least two. With only one, you either have to wash it in the evening and hope it dries, or wear it dirty. With two, the problem disappears, and both last longer because they get a chance to rest between uses.
By material
Cotton, bamboo, and viscose. Machine wash at 30 degrees on a gentle cycle, preferably in a laundry bag. Use mild detergent and no fabric softener - it leaves a film that makes the fabric less breathable.
Silk and satin. Hand wash in lukewarm water with detergent intended for delicate fabrics, preferably without enzymes. Never wring it out; press the water out in a towel.
Decorated models. Bows, braids, glitter, and fabric roses should be hand-washed. Machine washing can loosen the decorations or permanently flatten them.
Drying is what makes the difference
The tumble dryer is the single worst thing you can do to a head covering. The heat breaks down the elastic, and once the stretch is gone, it will never fit as well again.
Always leave it to dry flat on a towel. If you hang it up, the weight of the wet fabric pulls the shape out of place. Shape models with pleats or draping by hand while they are still damp.
The color
Patterned and brightly colored turbans should be washed separately the first few times. Some colors run when wet, especially onto light-colored garments. Direct sunlight also causes fading, so store them in a drawer or wardrobe rather than out in the open.
Storage
Folded in a drawer works for most turbans. Turbans with a bow, large knot, or visor are better stored flat with nothing on top, or on a wig stand if you have one. It is the shape you are protecting, not the fabric.
When it is time to replace it
When the elastic no longer holds, the fabric has become thin, or the color cannot be restored - it is time. A turban that slips all day is not being used, and replacing it is better than putting up with that.
See all turbans and head coverings or silk and satin sleep caps.