I have five.
There are so many excellent considerations outlined by others here if you're making a decision.
My age gap is 11 years with an average of almost 3 years between each child.
TBH it was like having two separate families once the oldest became teens. There is a huge difference between an 11 yo and a 13 yo.
For me, the thing that stood out the most for the two youngest children's experience of family life was all the losses they went through. One after another the older siblings left for university.
The two youngest were 7 and 10 when DD1 headed off, 10 and 13 when DS went, and at 13 and 16 they waved off DD2. Their memories of family life are different from the older DCs'. Even though we ate dinner together and tried to fit in a holiday together every year, they really only knew the older ones as teens who came and went. They were busy with school, jobs, sports, friends.
And now the youngest, DD4, is home with me all by herself, with another full school year before she heads off. The older ones come home for Christmas and DC4 may be home for the summer from university but not necessarily. Before long, I anticipate the oldest may get married and possibly decide to strike out on their own for Christmas. The youngest will not experience even that family event with all present and correct, when that happens.
I feel the youngest two were cheated out of much of family Ife just by don't if the fact that time marches on for the oldest.