In the spreadsheet below, he shared the various rounds of dilution the founders and early employees have to go through.
The earlier you join and invest in the company, the more you will be diluted. Dilution is a fact of life as a shareholder in a startup. Even after the company becomes profitable and there is no more financing related dilution, you will get diluted by ongoing option pool refreshes and M&A activity.
Read his detailed advise on dilution over here