they may feel empowered like mom is not coming in and just throwing away willy nilly. They can learn to make choices about what is most important to them. Of course if they are young they will need more guidance and choices limited. A 5 year old doesn’t need to be told to “get rid of 20 things in your room” but instead, say “Here are 2 old barbies. You can keep one and share one. Which one do you want to keep, this barbie or this one?” Of course, older kids and teens can be sent to their room with a timer and a garbage bag or box. I think having focused energy for 15 minutes might help over come the overwhelming feeling of it being an all day affair.
I have done the 5, 10, or 15 minute thing with my dh and dd. I have asked “give me x minutes” focused on straightening up. I set the timer and as soon as it dings, they can quit and go on to whatever they want to do. I believe the reason it works at my house is because I don’t harp on them to “give me a few more minutes” (or items to get rid of).