I wouldn't want to start TTCing #2 until #1 is at least two years old for BFing reasons. I know it is possible to BF throughout and pregnancy and then tandem-nurse, but sometimes woman do loose their milk completely during pregnancy and I wouldn't want to risk that happening before #1 is at least two years old. While I hope/expect to BF for quite a while longer than that, 2 years is my minimum goal. Also, I want to BF a total of at least 7 years for all my kids combined for breast-cancer reasons and this might not happen if they are born too close together since we will only be having two.
So DC#1 would be a minimum of 34mo, by the time #2 was born.
It also will be nice to have DC#1 enough older that they he/she play by themselves a little bit, walk steadily, etc. But I hope they are close enough together that the clothes, bedding, CDs etc. won't be too out-of-style to re-use.
ETA: I will be a WAHM. I do anthroposophical lifesharing w/ special needs adults, so "homemaking" will be my actual job anyway.