As you side your tiny house, you will end up with a pile of off cuts. These scrap pieces can actually be reused later by butt joining them into the length required. The most important thing to do when butt joining siding is to use "primed edges". This means that the siding was cut at the factory and is perfectly straight and perpendicular to the board. A good edge will result is a tight gap between the planks and a better looking result when it is all finished. When the factory cuts them, they then paint the whole board in primer and the factory cut edge will have primer painted over it to identify it as such.
A cut edge will not have primer on it, as you cut it with a saw after the board was coated in primer. As hard as you might try, the edge will not be perfectly straight nor perpendicular to the board. Irregular edges will result in an open butt joint and an unsightly gap in the siding which will allow rain to ingress more easily.
This is where organization comes into play. Butt joints require you to have a primed edge on the left side of one plank and the right side of another plank. If you measure and cut your planks from the same side, you will end up with an irregular number of planks with primed edges on one side versus the other. In other words, if you always measure from the left, all your off cuts will have primed edges on the right. If all your boards are "right side" "primed edge", you won't be able to make a butt joint that looks good.
By keeping track of how many right or left side primed edge boards you have left over, you can balance the stack to ensure you are able to use up your leftover boards for butt joints on long spans.
I separated the boards based on their primed and cut sides. Primed edges towards the outside, and boards with both cut sides in the middle. These boards are only usable in small sections where no butt joints are needed.
Ordering them from smallest to largest also helps make it easier to find the right piece when you are searching through your scraps.
I originally had a bunch of "right side" primed boards because I was measuring them all from the left. Seeing how I was disproportionately collecting right side primed boards, I began measuring from the right side to produce more "left side" primed boards. With the collection of both boards, I was able to use up my scrap pile with butt joints and reduce the number of boards I needed to purchase.
I used 42 boards to side the entire tiny house. I had 6 inches of display from each 8.25 inch board. The boards cost $8.45 per board, so the cost for siding was only $371.49! Tiny houses are great for tiny budgets!