I heard from my prenatal doctor that it is best to wait 2 years between kids to let your body completely heal.
It probably wouldn't really hurt you to have another baby a year after the first,but the doctor said 2 years is the perfect amount of healing time.
And about the siblings being closer due to age,my older brother is 18 months older than I am and we NEVER got along until I moved out and had my son(now we get along really well)my younger brother is 18 months younger than I am and we never really got along either until now.My sister is 7 years older than I am and we never got along either,we were too far apart in age,we weren't interested in the same things.So I think it all depends on the child's personality and how they interact with each other.It's not always easier with them really close in age,and it's not always easier with kids farther apart in age.It all depends on your kids.