Questions during procurement

Successful procurement of any system or service may be complicated. There are many potential traps for the inexperienced or unwary. Mistakes can be expensive. Some questions to ask:

Do the stated requirements fully and accurately reflect what is needed?
Are quality of service requirements realistic?
Is future evolution catered for?
Are the right standards included?
How to evaluate offers systematically?
How to deal with contract negotiations?
How to handle contract changes or recover from under-performance?