Regardless of the difficulty factor, we suggest not making any restrictions on the project details based on cost considerations, space concerns or even building codes. We suggest imposing these restrictions later as we have found that clients sometimes restrict the work they want based on false concerns about the cost of one aspect or its legality when in fact the additional cost is minimal and their legal concerns not valid.
We encourage documenting as many details as you can. If it is important, then it should be included. Often little consideration is given to issues such as interior lighting yet most people occupy their new space at night and have specific requirements for light. When light considerations are only made late in the project, it is not uncommon for the end result to reflect poor overall lighting. Adding the desired lighting during construction can end up being either very costly or not practical as in the case of vaulted ceilings. Had these issues been raised early on, specific design considerations could have been made to allow for the desired end result.