When do I change my vacuum pump fluid?

When should I replace my vacuum pump?
 
 

When do I change my vacuum pump fluid?

1. After a 100 hour break-in period of pump operation.
2. When the pump fluid becomes contaminated or is(and/or) discolored.
3. When condensation in the pump fluid is present.
4. Before and after the pump has been stored for a long period of time.