Over-washing your clothes is not necessary and can even damage the longevity of the garment.
Many garments can be aired/shaken out to prepare for another wear, and most stains can be spot cleaned before more aggressive measures are needed .
When in doubt, follow the care instructions on the garment label.
Wash Properly
Wash new, colorful garments on their own at first and not with lighter colors (Ex. Don't wash new denim jeans with white shirts).
Sorting by color is common - it may also help to sort by garment type (workwear/delicates or more expensive garments), fiber content, or temperature (warm vs. cold)
Use Lower Temperatures (When Appropriate)
Modern washing machines and detergents mean that we no longer need to boil our clothing to keep them clean and can generally avoid settings above “low” heat for your laundry wash cycle (excluding items like undergarments, bedsheets/towels, and some cotton garments that need an extra level of sanitation).
Skip the Dryer (When Possible)
Air drying is always the better option in preserving your garments for as long as possible, especially to avoid shrinkage in natural fibers and sweaters.
Do not leave clothes wet to avoid wrinkles.
Treat Stains Immediately
Spot treat stains as soon as possible– the longer you wait, the more likely a stain will be set into the fibers.
Do not dry garments until the stain is removed as heat can make the stains more permanent.