Hobby vs Interest

Hobby is something you practice or do regularly. Theoretically, it takes 21 days to form a hobby ( even if you dislike the action)

Interest is something that you have a liking for and you may or may not do it. You can get interested into something in a second. 

My hobby is swimming. 

I am very much interested in skydiving. But have never done it. 

Turn your interests into hobbies

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1. Hobby is more frequently practiced than an interest and will have precedence over interest.
2. Habit is following a routine, mostly mindlessly. Hobby and interest are intentional as well as mindful. Hobbies, interests give pleasure, not so sure about habits. Habits may actually be inconvenient or sometimes harmful. Habits shall normally have precedence over hobbies/interests.
3. Habits are inferior only to addictions which supersede everything else.

These are my observations and experience.

Now to answer your question:

The difference is on account of intention and compulsiveness. Whatever one does is an addiction if it supersedes everything else that one can or ought to do. Interests give intellectual pleasure when practiced. They are practiced only if the habits and hobbies so permit. Habits are mindless acts we do because of our conditioning,

Hobbies and interests, if followed can take a person to the top. Addictions ruin a person.

Habits prevent a person from going to the top or getting ruined.

The aforesaid are generalizations based on majority. Exceptions may exist.

I hope this helps in your quest.

https://www.quora.com/What-is-the-difference-between-a-hobby-and-a-habit

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English speakers use hobby to mean "something you like to do that is pursued vigorously in a systematic manner." 

=> Người nói tiếng Anh ( bản xứ) dùng "Hobby" với nghĩa là " 1 việc gì đó bạn thích làm mà nó được theo đuổi 1 cách mãnh liệt theo 1 thói quen có hệ thống. 

and "interest" for something you like to do 

=> "interest" cho những thứ mà bạn thích làm. 

Ex : Something you like to do is an "interest." If you only listen to music for pleasure, it is an interest. If you like to travel once in a while, that's an interest. Hobby is something you do systematically and with devotion. Stamp and coin collection are hobbies. Playing a musical instrument and joining non-professional or semi-professional performance group is a hobby. 

=> Thứ mà bạn thích làm là "interest".. Nếu bạn chỉ nghe nhạc để thưởng thức, nó là 1 "interest". Nếu bạn thích đi du lịch lâu lâu 1 lần, đó là 1 'interest". "Hobby" là thứ mà bạn làm 1 cách có thệ thống và với lòng tận tâm / hết lòng/ cống hiến... Con tem và tiền xu là những "hobbies". 

https://vn.answers.yahoo.com/question/index?qid=20100815012831AAg3Nz6