static method or non-static method using static field

Question

I have a static const std::vector<SomeType> field in my class. I have two private methods that uses this field (searching methods). They do not use another members of my class. Should they be define as static or normal methods?

What should I prefer? What are advantages/disadvantages?

Answer 1

Methods that reference only static members should generally be defined static. This lets you access these methods without creating an instance of a class, and also access them from static context (e.g. from a non-member function).

The only exception to this rule is when you need to make this access from a member function defined virtual. In this case you have no option to make your function static, because static functions cannot override virtual functions.