i have two kids, daughter at 4.5yrs old n son at 2 yrs. old. I have the same question about having the third baby.
Familly economy is of little concern.
Time management and personal ability to take care 3 kids are of middle concern.
The only concern that turn down the 3 kids proposal is that i want to reserve myself to take care of my parents and my husband's parents in case they are sick (They are in good health now). If one day they have any health problem and i hv no time to serve them coz i was fully occupied by my 3 kids, i would find guilty myself.