It's the gap that suits you and you feel you can cope with.
:yeahthat:

I have gaps of 2 1/2 years, 4 1/2 years and 7 years, so a bit bigger than most.
This last has been my favourite (so many helpers!!) but it doesn't sound like that what you're after .
2 1/2 years was good too although I found it hard while I was PG chasing after a toddler

I think all you can do is think about a few things & then decide what will work for you, eg - sleeping - do you want your eldest settled in a good sleep routine or are you not bothered by getting up at night - toilet training - do you want two in nappies at once - that kind of thing.
For some people a close age gap is a bit much, for others it works out very well.

FWIW - if I'd had my way I would have had all 4 much closer together - but life doesn't work out like that & I'm very happy with the gaps I have now