I can relate, when my teenagers were at home they were always forgetting to do designated chores…like put the trash out etc.

Now we have three cats, the two youngest use a litter tray, but the old girl Pheobe is now 16. She refuses to use the litter box but will go outside if the window is open, or she isn’t just feeling too tired and lazy and will find somewhere convenient to her to do her business.
This often isn’t found until a smell becomes obvious or we find it while looking for something.