I didn't think of it as child spacing, altho I was interested in the idea of natural child spacing.
I just nursed my ds whenever he asked, and I never pumped or used bottles or formula or pacifiers, and I wore my baby in a sling and slept with him and nursed him all through the night ... and we still cosleep and he still nurses at night... I didn't schedule, and I stayed home with him until he started preschool parttime (which I sorta regret... but that's another story)...
anyway, I didn't get my period back until the day after he turned two years old, so I guess it worked, in that regard...
but the main reason we did/do it is bc it felt/feels right for the baby/child/us/family. His greatest need is the breast for nourishment and comfort. This need is dwindling now as he gets older, but it is still there. I believe that as long as the child wants to nurse, it is a need. I meet this need as much as I can, but as he got older I began to set a few limits... this didn't start until he began preschool and couldn't nurse at school bc I wasn't there (one reason for regret, bc he wasn't ready to separate at that point)...
the limits might have waited until he turned 3 yo or so, when he seemed more emotionally ready to "wait till we get home" type of thing if I didn't want to nurse at the supermarket or whatever.
ETA: my ds didn't take to solid foods right away, and primarily nursed until around 15months when he started eating regular sold meals. But he didn't really eat a considerable amount of solid food until he was almost two years old at least. It turns out he has lots of allergies and food sensitivities, and knew that breastmilk was the best thing for him.