In the mechanical building world I use to work in, there were always "change orders"
Create a change order form, detailing what the customer wants to change/add to the order.
Next, you can add to the order form what the cost of this change/addition will be and the time frame it will set you back (give a new completion date, reflective of the addition/change).
Have both you and the customer sign off on the change order (literally, add a line for the customer and you to sign your signature) and your good to go. You've covered your butt and your customer knows exactly how the change effects the project.
Like Brock said, you always want to say yes, just make sure they know what that "Yes" entales.
The other thing that a change order form will do is eliminate the "friendly" factor in a project. Not that you can't be nice about changes, this is just a simple way to keep it buisiness like and no nonchalant "could we just do this" requests.
And than there is a record of what the customer has "signed off on" and they know exactly what to expect and you have a document that they signed when they start to say "this project was to be done on xxxxxx day" you can pull out the change order and remind them of what they agreed to. Their signature is right there.
Oh, make sure they sign before you do.
Rod True38835.1172222222
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