These service contracts guidelines are appropriate for large organisations and will be too detailed and formal for many self-employed, freelance suppliers and small businesses. Adapt the level of detail and formality according to your situation. ontracts and services agreements are essential business tools for professional trading and business relationships.
Without clearly defined and agreed contracts, misunderstandings can develop, expectations of client and provider (customer and supplier) fail to match, and all sorts of problems can occur. While the tradition and spirit of shaking hands on a verbal deal between two friends in business is helpful in underpinning a good trading relationship, it is sensible for significant supply arrangements to documented and agreed, usually by signatures.

Aside from the process of clearly agreeing and understanding the expectations between supplier and client, contracts or agreements also help if one or both of the original deal-makers one day move on, which can then give other people the problem of how to make sense of what might or might not have been agreed between the two parties.
The need to use formal signed trading agreements is markedly greater when you are managing supply on behalf of a company or employer. If you run your own business, are self-employed or freelance, then you have arguably more freedom to work with less formal controls - it's your business after all - and in many cases very detailed supply agreements can be an obstacle for small businesses, so adapt and interpret these guidelines according to your business size and level of liability.
These guidelines represent a prudent and safe approach. You can reduce the formality and detail according to your own situation, but be aware of the risks if you leave potentially contentious matters vague and open to dispute.