Historians of reddit how hard is it to become a historian ?

Depends what you mean! Anyone can become a historian for free in the sense of doing historical research and doing historical writing. There are many independent scholars out there. However, I assume you mean a professional historian attached to an institution, who gets paid a regular salary for being a historian. This is a lot tougher.

You need to get your Ph.D, which usually takes at least eight years and a lot of money. In the course of getting your doctorate, you will take increasingly difficult classes that require a great deal of reading, writing, and researching. Becoming a historian is definitely not for people who have difficulty reading long texts.

Once you have your doctorate, you will enter the job market, which frankly is hell in today's environment. There are very few tenure track and full time positions out there, and you will face strong competition from other aspiring historians. Once people get tenure track positions at a university they tend to keep them almost until they die, and with states around the country slashing budgets and imposing austerity and other market-style reforms on the university system, most universities aren't really coughing up massive sums of money to expand their humanities departments.

One of the best ways to make yourself stand out is to publish, publish and publish more. Universities want to hire people who have a strong record of publishing peer-reviewed books and articles. Many history PhDs end up playing the adjunct game -- teaching classes here and there, at various colleges and universities around town. This can give you a steady source of income, but usually without benefits and a very stressful schedule that involves a lot of commuting. It can also be demoralizing when you think you have your foot in the door at an institution due to being a long-standing adjunct, only to be overlooked in the rare occasion that a full-time position opens up.

Many of my friends from graduate school ended up doing jobs unrelated to their degree or teaching at the high school level.