To pick the right size bicycle, you want to measure your height, and specifically your inseam (inside leg), in proportion to the size of the bike frame. The inseam measurement determines the seat height, or the “stack.” Next, you must calculate the “reach,” which is the horizontal distance between the bottom of the frame and the head of the bike -- or, in layman’s terms, the distance between seat and handlebars.
Now you might be wondering: “I’m carrying a tube; why carry patches at all?” As insurance for the unforeseeable. Wirecutter senior editor Christine Ryan admits she didn’t use to pack them, but said, “I’ve regretted that decision when I’ve had a flat on a ride, used my spare tube, and then, half an hour later, had a second flat. Also, lots of people aren’t very good at figuring out—or don’t take the time to figure out—what caused their flat and remove the cause: thorn, eensy bit of glass, whatever. Then they promptly have a second flat, and everyone else laughs at them.”
Man, if you're starting out and you know you'll need several components for a bag... just get this. It will save you so much time picking everything out that even if you balk at the price (amazing value, by the way) I bet that if you did the math using your hourly wage and the time spent picking everything out and making sure it fits... you'd save a lot of money and a lot of irritation if you just got this. Just get this.