What is the most overlooked consideration?

What is the most overlooked consideration when buying a piece of audio gear? We all buy gear and we all have to make choices as to what component to get, what brand, etc. What is at the top of your criteria for choosing a piece and why? Synergy? reputation of brand ?hype your heard? it’s the best compliment to my system? warranty and service? I just wanted to try a cable? I only buy brands from the UK? Etc 

So you can tell what’s at the top of your list but mostly I want you to share what you think is a much overlooked consideration and why?
 

For myself I often think customer service gets overlooked as being very important.