Should I use typeclasses or not?

Question

I have some difficulties to understand when use and when not use typeclass in my code. I mean create my own, and not use already defined typeclasses, of c

Answer 1

You can often use a data type instead of a type-class, e.g.

data Repairable a = Repairable 
   { getRepairable :: a
   , isRepairable :: Bool
   , canBeRepairedWith :: [Tool] -> Bool  -- just to give an example of a function
   } 

Of course you need to pass this value explicitly, but this can be a good thing if you have multiple choices (e.g. think of Sum and Product as possible Monoids for numbers). Except that you have more or less the same expressiveness as for a type-class.