M.,
It took my husband and I almost 4 years to have our first baby, and that was with help of a fertility specialist. We wanted to have a sibling for our son but didn't want to go years again before having another. Not knowing how long it would take we started early. We needed to do invitro fertilization with our 2nd baby so we started that process when our son was 8 months old. IVF doesn't always work....so we were prepared to do a few cycles, however, it worked the first time - we were very lucky!!!!! We celebrated our son's first birthday and I was 3 months pregnant! Our boys are 18 months apart and it's been great. The little one grew right into all the baby stuff - swings, bouncy seats, toys, etc. Two in diapers, etc. Yes, it's a lot of work but on the other hand our older son never knew any different. He loved his brother from the get-go. He is a great role model for the little one. Our second son is growing and learning so much smply because he thinks he can do whatever his big brother can do. There is plenty of love and affection to go around. Our first son in no way was lacking for care or attention. And already at 2 and 3 1/2 years old the two of them are buddies.
Of course this is all my husband and I know. Some friends have waited 2-3 years between children and there are pros/cons both ways. It's great to have so much time to devote to one child for a few years. But then you start over again with the diapers, baby toys, etc. I think that would have been a bigger adjustment for our first child - overtaking his world with all that baby stuff. We had our 2nd child while the first was still using all that stuff. They learned to share early on too. I don't think there is a right or wrong for how to space out the age of your kids. Children need to be loved and feel secure. Either way it's whatever you are ready for. It's hard to imagine loving another child as much as you love your first but after you have him/her you realize how you could love 10 kids equally. Each is a special gift and unique in their own way.
Whenever you and your husband feel it's time...best of luck!