sewnseams

I'd like to make a couple of I Spy quilts for a couple kids I know but have a couple of questions. I've seen some really cute ideas here and am inspired. But I have a couple of questions.

Are the blocks used more than once? and if so, how many times should I use the same block in the quilt? or does it matter? I was thinking that if I used it a couple of times it could be a secondary game of concentration, looking for the matching block(s).

I'd like to make the quilts maybe the size of a twin or slightly smaller and I think I will make my blocks 4 1/2 or maybe 5". One child is 3 and the other 2 1/2.

Thanks in advance for your responses.