I don't have a specific number of hours played before I 'got it', but I had already done dozens, maybe close to a hundred landings on Mun and Minmus before I was actually able to travel to other planets. That's when I felt the game really opened up to me. Reaching a stable orbit was a big stepping stone for me, and actually landing on one of Kerbin's moons (which was Minmus, because many said it was the easier moon to land on) was probably my most memorable moment in gaming history. It was tense and immensely satisfying.
I kept doing this for at least a couple hundred hours of gameplay; going to other planets seemed like an impossible leap for me. But then I actually gave it a real shot, and I was surprised to find that it wasn't quite as hard as I kept thinking it would be. I could actually reach other planets, and I even landed on Duna. Now I have about 400 hours played on steam, and probably as much time played that is not recorded by steam. Perhaps I'm a slow player, but there is still so much more I need to do, and I'm looking forward to doing them.
