This is most certainly true when it comes to investments. Yes, you could put 100% of your savings in an index fund and forget about it, but that seems extreme, and also you have to live somewhere, so instead of paying rent and living in a non-ideal place you can't customize, you might as well buy a home that's a better fit for your family and has upside potential (and yes, no matter what people say, buying a house is most certainly an investment, a large one and potentially a bad one, but an investment nonetheless).

So now you have at least two big investment baskets that you really should watch carefully, on top of your job, and all those other life things that, as mentioned by another commenter, do get easier once you've done them a few times (like picking a health plan or knowing the basics about car maintenance), but each one has a learning curve and change with technology or policy. And it's a very long list.