I am an internist in my second year. What is a good number of new patients a month to add in order to build a practice in a reasonable amount of time?

The answer depends entirely on other factors in the practice, especially your overhead and the general business model. 

So, a mature practice with a typical business model has about 2,500 patients per physician (that is, patients you have seen in the past two years). 

You could just estimate how many you’d need to see a month to get there. 

But, there is no sense trying to get 60 patients a day if you can’t possibly handle that. 

And, for another example, some these days are setting up very low-overhead practices which require far smaller patient panels to make ends meet. 

So, I’d say you need a robust business plan, projecting your costs against the revenue per patient, at a minimum, and see where you need to go. 
