What is an English words which describes that something is different for different people, or in other words, it's kind of exclusive to the person they belong to.
For example I want to say that there is nothing like "the-best-sleeping-duration". Sleep requirements vary with people. Different people have different sleep requirements.
Likewise, I want to say that there is nothing like the best method to study. Different methods are best-suited for different people. It's kind of subjective.
I would go with personal based on your example.
1 : of, relating to, or affecting a particular person
While subjective is a synonym for personal, it has a connotation that you can control it. I wouldn't say your requirement for sleep is something you can change as easily as your opinion on a matter. Antonyms for subjective include objective, unbiased, and unemotional. Antonyms for personal include common, public, and general.
I think you may mean subjective.
subjective
/səbˈdʒɛktɪv/
adjective
based on or influenced by personal feelings, tastes, or opinions. "his views are highly subjective"
synonyms: personal, personalized, individual, internal, emotional, instinctive, intuitive, impressionistic;
there can be a distinction between the denotative meaning of a word and its connotative meaning. in some cases the different understanding between people can be associated with differences in the connotations of a word
The word is connotation. It's the emotional "baggage" a word carries with different people based on their individual experience with said word.
