If you are building or maintaining, you hate the delay of waiting for a certain size fastener. Spend the money, buy this kit and you handle 75% of the one-off needs for nuts and bolts. The next step is to pick up a parts organizer at Harbor Freight, and keep a post-it pad handy. Write down what you took from the buffer store, replace what you used in your next ACS order, and you have an evergreen buffer stock. The build gets so much more enjoyable as I learn how to avoid delays and frustration! Hint - if building in metal or fiberglass, also get a nutplate assortment. If fabric, tinnerman clips. If wood, God help you.