Although no one wants to be in the position where an element of the design or a piece of gear just isn't working, it happens. We all use a system wether it be Vectorworks, AutoCAD, old school paper & pencil drafting or making & triple checking gear lists, to ensure layout is solid and that spare fixtures can be built into the job. However, eventually you will find yourself in a situation where it's just not going to happen on time. Sometimes it's something small and only noticeable to the designer (which sounds like the better option, but not always). Sometimes it's a rather significant part of the design that the client isn't going to miss that they aren't seeing.
What I'm getting at is that at the end of the day, you have to have confidence in yourself and your tech skills. Most of the time when you're gigging, you are familiar with the gear being used - even if you haven't used that specific piece of gear, you get it. How many times have you been on a show with a moving light, LED or a connector torn apart to the point where a bystander who isn't in the industry would say a little prayer for you as they strolled past... these are the scenarios where you stay calm under the pressure and have faith in your experience and knowledge.
I have built up a toolbox over the years that helps put me in a position to handle almost anything when out on a show. Sometimes I take some hits over the neatness and how organized my toolbox is (same tools go back in the same spot...always!). If grabbing for a tool is second nature, then that's one less distraction from the task at hand.
Let's circle back around. No one likes to punt. No one likes to disappoint their clients and designers. I'm not going to say that this is never going to happen, it has to happen in order for you to grow as a tech. But how you handle your punts will help you grow as a tech that completes third down time and time again. -Beth, Lead Production Tech
"The size of your success is measured by the strength of your desire; the size of your dream; and how you handle disappointment along the way" - Robert Kiyosaki