How did you chose to have more kids or decide if you were one and done?

DS just turned one and we talk a lot about having a second. That likely wouldn't happen until next year if we do decide. But the more we talk about it the more it seems likely we are one and done and it's kind of sad to think about that. There are a lot of factors, such as cost, which is our biggest thing. I am not really sure if we would be able to pay for two in daycare, plus save for retirement, save for LO college, and not be completely broke doing it. Also, DS was so tough his first year that it is sort of traumatizing to think it could happen a second time.