My career is very important to me and I am fighting for shreds of it as it is. DCs are 6, 4, and 2 years old. If we had another we would have stuck to that pattern, so the chance is gone. (not that we were that tempted anyway!)
There is a tiny voice in my head that would be happy to be talked into another child, and if money were no objection I would be very happy to have another, because then I could get in more help with basically everything.
BUT we have our hands full with our three, we cannot buy in any more help, I am really not interested in any more night wakings, I really don't want to take more time out of my career, I really cannot find an ounce of attention to give to a fourth child, I wouldn't want to decimate my non-existent me time, basically the list goes on and on. I would be unhappy taking time out of my day for a fourth child's appointments: doctor, school, it really adds up!! especially as they get older.
I remember how easy having two kids was. Right now, I am not thinking that 3 kids are easy, so I will listen to this voice. On the other hand, having four kids is really cute, but definitely not for us.
Also, I am getting a bit too old for all this now (turning 40 in december).
Basically, to have 4 kids you need to be a 100% parenting team / a SAHM or SAHD from the bottom of your heart, unless you have some spare money for 2 nannies to help out etc….