Best age gap in your opinion?

i currently have 2 children 20 months apart they are 7 weeks and 21 months, i like this age gap a lot, we are starting to get used to routine and stuff, my eldest is a good baby and although my daughter has got reflux i am getting used to it and i hate to say it but i feel i am sooo broody, we want a large family so that might be why, i started my period yesterday (we are using the family planning method), we know we are not going to try now but i was wondering those who do have kids 15 months or so apart (strangely enough that would have been the age gap of my kids if i didn't miscarry the first time) and also how did you find being pregnant with two little kids.