When and How should a Company Train its Employees?

Consider one type of industry in terms of the type and nature of safety training organization in that industry should provide (construction, office/professional, manufacturing, retail, food service, etc.). This could be your own company. And answer the following questions below.

Does the size of the company affect the recommended training?

Would you train only new hires, or conduct regular, on-going training?

In what situations would you consider hiring a consultant to do the safety training?