Just a few ideas for looking after equipment
Strengthen all the corners of boxes (jigsaws, games, construction sets) with clear heavy duty tape so that the boxes are more robust.
Use Discovery Time to teach students how to look after things. Insist that when lids are removed they are placed under the box for safe keeping and that pieces are not spread all over the room.
Keep large pieces of fabric (1-2 metres is good) for the students to spread out on the floor when using construction material (LEGO etc). This defines the area and keeps all the pieces together. When packing up it is easy to gather up the corners and collect all the bits at once.