The company you are cleaning for needs to feel it's getting as much as possible for their money. Don't mention all specifics, surprise them with the little extra's that way they will love you. It's normal to raise the price of a contract at the start of each year, if you have already quoted then tell them the price increase will be due soon to the rise in products, electricity etc but not to worry you will throw in cleaning their towels for free, that way you won't loose any money.