Hi Deana,
I believe you are quite correct, a list of what will be cleaned and how often, will prevent any mis-understandings in both your markets. This way you will prevent any "contract creep" ie. clients adding things on at a later date, always stating that they thought that was included!
You, of course should also supply any client with your "terms and conditions" and a "service agreement". Again these documents, which form part of the entire contract, will protect both your business and your client's interests as well.
You must also get a written partnership agreement in place, spelling out each of your rights and obligations before any trading takes place. You might well be the best of friends now, but if someone fails to pull their weight, or wishes to sell the business, what then?
Take professional advice on all the above, yes it will cost a fair bit of money, however the willingness of both prospective partners to set up things properly will speak volumes as to how serious you both are to make a real go of your proposed new venture.
Regards,
Rob