Most contract awards are mandatory use. Purchase requisitions are used to establish and renew contract awards. Once a contract has expired, it is no longer valid. It is available on-line in SYSM or in hard copy. Training is considered a professional service.
Different percentages apply.
Always state exactly what you want. Avoid unique requirements. List enough essential characteristics to ensure that any product which meets all of them as a minimum would be sufficient to meet your needs. Make sure all of the potential bidders receive exactly the same information. Similarity of products.