Start with the label
New does not mean durable. Check whether the garment is machine washable, hand wash, dry clean only, cold wash or otherwise restricted before the first cleaning.
Separate unstable colors
Dark denim, saturated colors and garments whose labels warn about color transfer should be washed separately from whites and light colors. The first washes are when you have the least evidence about dye stability.
Choose detergent and temperature from the garment
Use the detergent directions and a temperature that fits the most restrictive item in the load. Cold water is a conservative starting point for many dark new garments, but it is not a universal rule for every fabric or soil type.
Protect shape and finishes
Close fasteners, turn decorated or dark garments inside out when appropriate, use a compatible cycle and avoid high dryer heat unless the label permits it. Stretch fibers, prints, coatings and trims may have lower limits than the main fabric.
Build a safer first-load plan
If you are unsure whether a new item belongs with an existing load, use the Wash Together Checker and treat a care-label conflict or unstable dye as a reason to separate rather than guess.
Garment care labels, appliance manuals and laundry-product directions can be more specific than a general guide. Use them when they set a tighter limit.