We wanted 3. But stopped at 2. I have horrible pregnancies and found the baby stage very hard (especially DS1 for health/non sleeping reasons). But I was prepared to "sacrifice" 2 years to get past the hard bit.
However both DC are now in primary school and I totally underestimated the time and mental load associated.
Without counting the recently diagnosed ADHD (which is accompanied by 3 appointments a week), medically we've had:
Migraines, speech therapy, braces, salmonella poisoning requiring a 4 night hospital stay, another virus requiring a night in hospital, glasses, various sprains needing xrays as well as your standard vaccinations and illnesses and dentist appointments.
School wise there's homework, friendship problems, parties, play dates, bullying and yesterday DS1 came home with huge scratches down his face so having to talk to school about that.
Then there's the clubs. Ok its "optional" but very nice to have. Mine do 2 sports each.
I love them dearly but am worried about the teenage years and salute anyone who manages to have more than 2 DC!