It's all about time

I'm now at the point where I can make a crane in about 5 minutes. So each day's 10 cranes take me 50 minutes or so. I'd like to get that down to about 45 or 40 minutes. At an average of 45 minutes a day, I only have left ... (pause while I get out the calculator) ... about 69.75 hours of paper folding. Whoa.

My total time investment: 100 days X 45 minutes per day = 4,500 minutes = 75 hours. That's ... what? ... three full days and three hours.