I get mine back really early.
: Like 3 months. I'm one of those rare ones I guess. None of my kiddos have ever had a bottle, nor a drop of formula, they eat all hours and they've all been 8-9 months before they've had any solids.
And, when I was tandeming #2 and #1 it still came back soon too.
I know my grandmother nursed all her kiddos for years, and a significant number of them are 18 months apart. I think mine would all be at least that if I didn't use birth control.
I got preggo with #2 on the FIRST TRY (yes I tried) when DD was exclusively bf around 8 months. I saw some egg white and I figured...sure, go for it.
DH of course didn't think it would work.
Since it was not fun nursing during pregnancy I purposefully used birth control after the next two were born to have more of a space!