This is very basic question so pardon me if it bored you.
I have 2 options:
a)Reduce the number of lines of code in helper and instead add more code in apex controller
b)Increase lines of code in lightning component helper.
By increase in lines of code in helper, what I mean is increase in "if else" constructs, adding 1 or 2 switch statements, and 1 or 2 additional methods. Pros in this approach is I can avoid a server call . My helper already has 10-12 methods , so is it advisable to add more code in it or make a server call?
Hence a more wider question is that should as much business logic be kept at client side as possible, or keep client side clean and leverage server for processing business logic.