It depends on the heir, I always start with a kid of my sim and move to the next generation. There’s one constant: I always build their house first. I used to take all the money earned with me and a lot of convenient items in inventories of parents, but nowadays I prefer them to start from scratch financially (except for my current heir because she lives in an apartment building and I figured she didn’t have to pay for the other households in there; she started living in one part of the building with cheap furniture).