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Put it in writing!
Whether you hire independent contractors to perform services for your business or you provide services as an independent contractor, before any services are performed make sure you have a written contract.
The contract (the independent contractor agreement) should stipulate the terms of the agreement. For example, it should include the rights and obligations of the service provider and the recipient of the services.
The contract must be dated and singed by the appropriate parties.
There is excellent legal software to produce such an agreement plus a variety of other legal documents commonly used by businesses.
Generally, the software takes you through a series a series of questions to which you provide the answer and the program formulates an independent contractor agreement to fit your situation.