Many interior designers I speak with express concern when charging a mark-up, even some that have been in the business for years, because they assume that their clients will immediately question how accurate their mark ups are, and that this will eventually undermine their trust.
As a business manager, I’ve learned that clients will pay what they agree to pay 9 out of 10 times, and that when problems do arise, they typically do so based on simple, honest mistakes. You truly, accidentally double charge for a cushion. So the first thing the client thinks is, “What else have you double charged me for?” Then they’ll want an accounting of everything.
That’s when you’ll need back up. Lots of interior designers use Quickbooks, because it’s easy to use and their accountants love it.
However, I always suggest designers use software developed specifically for the industry, be it Design Manager, Studio Designer or Studio Webware, to enable them to pull up reports specific to a project, down to a particular room, by PO, by invoice, to determine when something was purchased, when it was delivered and, most importantly, how much was charged.
Having access to this kind of information readily available has an incredible calming effect on clients when situations such as these arise. Sometimes back up invoices are a prerequisite required for whatever reason as part of the client’s way of doing business, like if they have a business manager or family office that requests them. So beyond your client rapport and relationship, trust sometimes boils down to how good your systems and back up are.