This is the biggest collage I've ever worked on. It's 24"x36" and while my materials haven't changed (still just using mail order catalogs and magazines)... Well, besides blowing through glue sticks, it means that I'm having to change the way I construct, because each section has to be built individually. It's a good challenge for me and I am currently walking around the house with this huge canvas and setting it in different spots in the house to look at it from different angles, trying to pick out problem spots.
My kids had plenty of "problem spots" they could find... They think it needs a sun and some birds...as for me, it's a little more subtle to figure it all out. Might have to be done for the day and come back tomorrow.