Why do hook sizes matter?

       Why do hook sizes matter?

  The size of the hook will determine the size of the stitch. And the size of the stitch will determine the size of the finished item. The yarn size will also affect the size of the stitch. If I crochet a baby blanket, say, with a huge hook and rug yarn, I'll end up with a much larger blanket than I would if I used a tiny hook and that cotton thread, even if I use the same pattern. The huge hook and yarn would be big enough for a kid and quite rough and the tiny hook and thread would be about the size of a hanky. Most yarns and threads will have a suggested size of crochet hook listed on the label If you wrap yarn around a 3mm diameter stick and then around a 7mm diameter stick, will they both give you the same size loop? No, of course not lol. One will be tighter and one looser. The same is true of the sizes of crochet hook hope this helps