My DS1 loves lego and has quite a few boxes where you make specific models following the instructions. I don't know how to store all of these though!
Once he has made them he pretty much doesn't play with them as they are in the box and I don't want them to get mixed up. However, I am not sure if I should just put it all together and mix up the sets. If I don't do that, I need to find a way of storing it. I know that lego make storage boxes that look like bits of lego - however, I am reluctant to buy one to store each set as that would take up a lot of room and cost a lot.
Do you mix yours up in one big box? If not, how do I keep them separate but so he can easily access them (but his little brother can't!)