“This vacuum cleaner bag isn’t full yet.  I don’t need to change it.”

No, the bag might not be ready to burst, but if it’s too full, it will negatively impact suction power.  Live large and change your vacuum cleaner bag when it’s ¾ full.

“A little salt will take this red wine stain right out!”

Just the opposite!  The tannins in the wine will react with the salt to set the stain permanently.

“I don’t see the stain anymore.  I must have gotten it all up.”