This is all very hypothetical atm.
DH and I have one DC who is just over 4 months old. We are sure we would like to have another at some point and for DC1 to have a sibling.
DC1 is such a joy to us, but I will freely admit I find the sleepless nights, feeding etc with a newborn very tough. I really don't think I could go back to 'the baby stage' with another DC if we were to wait till DC1 is much older. It sounds awful, but I really want to be completely past this stage quickly. If we waited and had another DC in a few years I am just conscious that we would have to start again in a way.
I have also heard people say that DCs who are closer in age are 'better friends' but I don't think that is strictly true based on families I know.
My question is, AWBU to plan to have a gap of 18 months or less between DCs? We conceived quite quickly with DC1, but appreciate this might not be the case with DC2. My question is purely about our planning the gap - I know nothing is at all guaranteed!