I think it is great that you are planning this so carefully. It is a question that is hard to answer. SO many factors come into play.
When we were planning our one and only now 14 yr old daughter, we ran a lot of numbers. Hubby and I are very much numbers people and planners.
We prioritized things important to us, namely, I would be a SAHM. I do not regret that decision at all. EDIT: another HUGE priority was that we would always have our date night weekly. It is SO important to keep the connection with Hubby. We have only missed date night occasionally due to sickness. We still go out at least once a week.
While planning, also consider the college costs, etc. I know it seems tough when they are newborns but it is better than being hit with $40,000 a yr for college!! Before our daughter was born her college fund was established. We made plans to contribute a minimum of $10,000 per year by her birthday each year. On the very good years, we put in more just in case the next year might not go so well.
We also took into consideration of a wedding (we've already offered her the $$ to use on a house or something vs a wedding, LOL), first car ( I've been driving her first car for 3 yrs and she will get it when she gets her license) We value safety and her first car is very nice and SAFE.
A lot of people don't feel the need to provide college funding for their children. We feel it is our duty as her parents to provide for her and set her up debt free as she goes out on her own.
Then we look at the day to day expenses. Sometimes there will be unexpected expenses. I'll say that our expenses now with daughter are higher than when she was younger. She is a varsity cheerleader for the upcoming year and we have already spent $1200 and school has not started! She's also accomplished in orchestra and new violins are not cheap ($3000), then you have laptops, etc to keep up with school.
I realize I am talking WAY down the road from where you are considering now. I'm just saying that our expenses are higher now since she has gotten older.
I think it is great that you are planning but don't "overplan" either. Enjoy your family!!!
Yes, our retirement is done. Your retirement is very important
We only have about 4 yrs left with our "baby" at home. They grow up TOO fast.