Savings beginner with questions about the plausibility of the "rough" plan

As long as only one partner in a marriage is working, they can use the tax allowance of the non-working partner. The higher the marginal tax rate of the working partner, the greater the resulting relief - in extreme cases ~45% of the current allowance.

A second income therefore only actually brings more money into the household budget if it significantly exceeds the savings that are now lost from the first income.

Ah, okay, I understand! (Grundfreibetrag derzeit 8.652 €/a, 45 % davon sind 3893,40 €/a oder 324 €/Monat. ... Aus meiner Sicht praktisch nicht relevant, da dürften die hier diskutierten Fälle drüber liegen. Danke für die Erläuterung!)

That is not correct. Both allowances are always applied to the total income. In your example, the second income would effectively pay 45% tax, no matter how high it is. The tax classes also do not play a role in the annual consideration.

I agree with Willo7777. Only the second Arbeitnehmerpauschbetrag of €1000 is lost. In return, a minor (flat-taxed) job could turn the whole calculation upside down. It is indeed the case that the taxpayer with €100K income + approx. €5K flat-taxed job of the spouse is better off than the couple with 2x €52.5K.

Very interesting regarding splitting. Luckily, we have a tax office that deals with this for a lot of money. On the topic "wife goes to work or stays at home," here is another aspect: My wife earns per year (30h per week) what I make in a month. She has a net income of about 1300 EUR per month. We pay almost 800 EUR per month for the daycare and my wife needs a car for work. I estimate that at around 300 EUR per month. Why do you think she goes to work? Because of the money?

Money isn’t everything and the women in the "Osten" might think a bit differently than those in the "West."

Regards, Steffen

Good that my understanding of splitting has now been straightened out again. Somehow I found the argument convincing ... for whatever reason. Still, thanks for _all_ contributions on the topic.