Service class layer BLL

Question

It is bad practice to have a very extensive method within my service class?

Or it would be better to divide them when possible into smaller methods in the same class and call them?

Answer 1

Very extensive methods, in any layer, are bad. The best is to divide it into smaller, reusable methods, where each method is concerned with a specific part of the processing. The "submethods" need not be public (and they better not be) if it makes no sense to be called by other classes.