For a number of years now, as my son is growing up, I make it a point to try to remember what it was like to be "that age". The life lessons are important, and I nag and lecture and even raise my voice sometimes, because that kind of stuff needs to sink in in order for him to be the best adult he can be. But there are other things, like building a blanket fort (pictured above), that are necessary for the kid to just be a kid. So the pillows and sofa cushions and blankets and sheets and whatever else he can find are strewn all over the bedroom...so what? Yes, you'll have to help pick it all up (because as all mothers know, MAKING the mess is far more fun than CLEANING UP the mess!) And yes, you'll probably have to do some laundry. And maybe the cushion will get torn or stained. In the grand scheme of life, I think it's more important to let the kid build something out of his imagination, and put it together so it works, than keep the sofa cushions pristine.
Well, actually, we have 4 rather large dogs, so nothing in our house is pristine.
These days especially, when 5-year-olds can work iPhones better than their middle-aged grandparents and planning their extracurricular activities for college entrance starts in preschool, working some (semi-forbidden) hands-on, old fashioned playtime into a kid's day is a GOOD thing! Drawings in chalk on the sidewalk or driveway will wash off. Strips cut from plastic bags to make into friendship bracelets that never actually get made can be thrown away. Muddy shoes from going fishing with the boys in the "pond" across the street can be dried and brushed off.
And blanket forts are cool.