I have some wealthier sims, but I like playing with different types of households. Some are "house poor", meaning they have a big house but not much cash.
Sending children to university and splitting up money with heirs is one way to manage the money. I like some of my sims to be wealthy so they earn money through investments. That's not based on favoritism but on their already having a lot of money, so they accrue interest or earn dividends or rents.
I think they could do more with business and investments. There is the option to burn money or donate it if you really want to get rid of a bit. Having an expensive house with bills will drain your sims too.
