'Throwing' vendors out is not nice, especially when you use their component out of spec :-)
In any case you suggestion is very good. I like to perform a lifetest on a relay because the specification is not always clear. When you switch capacitive and inductive loads you can get stress on the contacts due to the current and voltage spikes. Try to find this in the specification! There is some standardization in relays (TV-5, TV-8) which tells sometimes about inrush current capabilities, but it is always best to do switch on/off cycles. I have seen several occasions in the past were such a test would had filtered out a design problem.
