Like any professional service, providing translation services is a balancing act between three customer requirements – Good, Fast and Cheap.
You will hear the same argument presented in a more traditional way using Time, Quality and Budget. The theory is that if you push too hard on one requirement another will suffer.
An example in our world would be a rush project that requires a linguist to work overtime. Typically that requires a higher price. That would mean that you accomplish good and fast but cheap certainly doesn’t apply any longer. Another example would be the same rush project with a time frame that requires a shortcut to meet the deadline. Good linguists won’t take shortcuts. Shortcuts typically cheat quality assurance measures so you now might get fast and cheap but now good doesn’t apply.
I think the point is to find the closest possible point of balance between all three requirements. In other words the image below would be translation nirvana. When scoping an assignment with your translation vendor, just remember that if they are truly honest with you they will help you to find this balance. When they are faced with an excessive challenge related to any of the three requirements, they should let you know what they will do to mitigate the risks associated with working out of balance.