My DS1 was 15 months when DS2 was born. They both napped at the same time during the day and I got to sleep, and now they are best friends which is just wonderful. It was also good practice for 2 years later when I had twins as I was well used to dealing with 2 babies at once. Having my family close together has also minimised the total time I have had to take out of the workforce, as I have not worked since I was 6 months pg with DS1.

On the downside I would have liked to be able to concentrate on each baby a little more when they arrived, but as I was always distracted with other babies this never happened.

As has already been said there is no ideal age gap, all gaps have pros and cons you just have to work out what your own priorities are.