Defining Clear Objectives and Goals for Load Testing

A question I get asked a lot is ‘What are the entry criteria for load testing?’ Before I go on, I’d like to clarify what I mean by load testing. Sometimes I see the term confused with; interchanged with or lumped in with performance testing orperformance testing tool. When I refer to types of performance testing, I mean end to end response time, including rendering, of a single user. By load testing and stress testing I mean, how does the system including network, servers, machines and database cope when multiple users are using it at the same time?