The wet washing ends up sitting in the machine for hours and eventually begins to smell damp and disgusting.
But how long can you leave it in the washing machine before this happens?
If this is something you've ever been curious about, then you're in luck as an expert from the Whirlpool Institute of Fabric Science, Lucinda Ottusch, has revealed the answer- and it might surprise you.
According to the expert, washing can be left for almost an entire day, between eight to 12 hours, before being hung up to dry - but no longer.
And they're not the only ones who think this - Martha Stewart also agrees.
Speaking to Today she explained that she doesn't think it's an issue to leave your washing in the machine overnight.
She said: "I would say that it's perfectly all right.
"I mean, don't leave it for a long time... don’t leave it for a week. If you get up in the morning and throw it in the dryer, it should probably be OK."
So how do you know whether you've left it too long and if you need to re-wash?
Simple, just trust your nose!
Stewart says: "One way you can kind of tell is if it smells all right.
"That mould and that bacteria that starts to grow on damp clothes and environments, that's very pungent."
Despite these words of advice, it's still a good idea to hang your washing up sooner rather than later if you can.
And even Stewart adds not "to make a habit" of having half-finished laundry.