I was amazed at how over-engineered their first rockets were. Having always played career mode I was 'forced' to do the minimum, getting to the Mun with only 2

I was amazed at how over-engineered their first rockets were. Having always played career mode I was 'forced' to do the minimum, getting to the Mun with only 2 or 3 engines total. Flying to other planets is really difficult, something I still can't reliably do with hundreds of hours played. I've only sent probes to 3 of the other planets (Duna, Eve, Jool). It can get monotonous, but when I play I am strongly motivated by trying to achieve something I never have before. (Or if I'm playing mods such as 'Real Solar System', but that's another step up again in difficulty).