Leaving a 3/4-full laundry load in the washer for about 21 hours can have several consequences, and there are valid reasons to consider washing the load again. Here are some potential issues that could arise:
Smell and mildew: As you mentioned, the most apparent problem is that the clothes might develop a musty smell due to the damp environment in the washer, especially if the laundry load was still wet when left for an extended period. Mildew and bacteria can grow in damp conditions, leading to unpleasant odors on the clothes.
Bacterial growth: Wet clothes left in a closed, warm environment can encourage bacterial growth. If the laundry load wasn't properly cleaned during the initial wash cycle, bacteria may have had time to multiply.
Stains and setting: Any stains present on the clothes might set further into the fabric over time. This can make it more challenging to remove the stains effectively in the next wash cycle.
Drying time: If the clothes were partially dried during the initial cycle and then left for an extended period, they might become wrinkled, making it more difficult to get them back to their original condition during the drying process.
Efficiency: Leaving a partially washed load for a long time and then re-washing it can lead to wasted water, detergent, and energy, impacting the overall efficiency of the laundry process.
While the clothes might not necessarily be unclean after the initial wash cycle, they could still suffer from the issues mentioned above. To avoid potential problems, it's generally best to remove the clothes promptly from the washing machine after the cycle is complete and either dry them immediately or rewash them if needed.
If the clothes do have a musty smell or show signs of bacterial growth or stains, it's advisable to rewash them. To prevent similar issues in the future, try to set a reminder or alarm to prompt you to move the clothes to the dryer or hang them up for air-drying after each washing machine cycle. This practice will help keep your laundry fresh and prevent potential issues associated with leaving damp clothes in the washer for extended periods.