Spills and stains are generally much easier to clean up when you attack them right away. When you treat that tomato sauce splatter on your dress shirt without delay, for instance, it offers little resistance.
If you wait until the next day, you’ll be sporting a permanent-looking red polka dot that you’ll expend a lot more cleaning solution and time getting out. Similarly, clothing or carpet stains are easiest to remove when they’re fresh.
The longer you wait, the more chance the stain has to set. Bond cleaning is also easier if it done this way.
The rare exception to this rule: Mud tracked onto your carpet is easiest to clean when you’ve let it dry first. Wait until it’s bone dry and crumbly; then just vacuum it up.