When taking on an Interior Design project there are a lot of boxes to be checked off. There are so many moving parts and so many details that make up the design. It is very easy to overlook some details.
As a solo designer my hands can get pretty full and I do miss some things during design projects. (I am strongly considering hiring an assistant to make sure this doesn't happen too often.)
I get so focused on one particular detail that I miss another. I definitely don't like making mistakes but I also know that I have to give myself grace. I am a one woman show and I am not perfect even though I really want to be. I really get broken up about it when something does slip through the cracks and I'm thinking to myself... how in the world did I miss that!
Even though I've done this process numerous times each job is still different and anything can happen but it's what you do to fix it. Not all mistakes end up being terrible sometimes they are better than the original plan and sometimes they really are terrible and you have to make the client happy and fix the mistakes. As long as it's fixable you should fix it and if it's not then something has to be done to make it right.
Clients do pay top dollar for your experience and expertise so mishaps aren't what they are expecting.
With that being said it's important to take your time and make your lists and check them twice. Be really transparent with your clients and own up to your mistakes or things that were simply just overlooked. People will respect your honesty and you solving the problems so they don't have to worry.