I do 8 loads a week so far... 2 adults 1 toddler

Wednesday
1 light load
1 dark load
1 nappy load

Saturday
1 light load
1 dark load
1 nappy load
1 bedding load
1 towel load

I don't think the next baby will add too much to the washing except in nappies, I can see another 2 loads of nappies a week when he goes into the MCN's.