Cindy here! I can't tell you how many times I've dug through my paper supply, found the perfect paper, but not had quite enough of it to do what I'd hoped. Check out this layout:
I had exactly two sheets of the background cardstock and nothing else on hand that was quite what I wanted. Yet, I really wanted to back my title and make journaling strips from that same cardstock. My solution was to cut out a chunk of the cardstock that would be hidden behind the photos.
I do this ALL the time. Probably half of my layouts have visible chunks missing from them if you look at the backside. Fortunately, this is hidden in the album!
Here's another example. The finished layout looks like this:
I didn't enough of the creamy cardstock to make a complete circle, nor did I have enough of the green patterned paper to back the photo strip. Here's what the layout looked like before I adhered everything. As you can see, I only used tiny strips of patterned paper behind the photo strip, and the 'circle' is actually two pieces that were *barely* big enough to fit behind the photos.