How long is the conversion process into Traditional Orthodox and Modern Orthodox? What is the minimum time period in most cases? I know converts can spend years preparing until they actually finalise their conversion.
From the Rabbinical Council of America (RCA) conversion FAQ:
The amount of time for a convert to be prepared for conversion varies from case to case, depending upon the level of knowledge and experience that preceded the quest for conversion and many other factors. A minimum of two years of study and experiential growth is generally recommended though individual circumstances may vary in this regard. During this time, the candidate will be in communication with the Beit Din to review his or her progress, and make any necessary adjustments or decisions as to the remaining course of study and personal growth.
No specified time is usually minimum is one (1) year. But this can vary, it depends on the person who will become. Study the Torah, Talmud and other sacred books is important, and more than that, is to practice, the practice is essential. But all of rabbinic monitoring.