For the first one we didn't care but found out inadvertently during a sonogram because my son had his legs spread out for all the world to see. It was kind of obvious we were having a boy.
For the second, I wanted to know for practical reasons. We had a ton of baby boy clothes, boy toys, boy furniture, yadda yadda yadda that was sitting in bins. I wanted to know whether or not we needed to start unpacking that stuff or donate it and start buying/asking for girl stuff. Turns out we had to get rid of the boy stuff, keep the gender neutral stuff, and buy/ask for girl stuff.