The most common answer a startup will give to "what is a brand," is something along the lines of "logo," or a "visual representation of your company." While the visuals are a key part in making a brand, they do not describe its entirety. Marty Neumeier, author of the Brand Gap describes it this way:
The brand is a gut feeling. It's an emotion felt by someone after interacting with an entity, usually a business.
What is a brand? A gut-feeling, don't let anyone else tell you otherwise.
If you plan on having an element of your brand identity for a long time, say your name or your logo, it's imperative to research and make sure it will stand the test of time. Reason being that you want names and logos to be around for a while. You shouldn't push out these elements unless you're prepared to have them stick around for years.
However, when it comes to items that can (and should) adapt, your goal is to move fast, do good work, and change as needed. Pretty much everything your customer comes into contact with like your website, collateral, software, etc is going to adapt with technology and alongside user testing. In this case, make good stuff, test, and iterate.
It's astonishing the amount of business owners and sales people who want to be better. They want more customers, they want higher value customers, more of anything that will help them get to the next level. Where this gets interesting is how few of them are willing to do something different to make an impact.
They repeat the same message they have for years, fear to break the mold, but expect that things will change. They pour countless amounts of dollars into marketing, expecting that somehow the same old message will get through.
It's like running on a treadmill. No matter how fast you go, you stay in the same place. If you want to go somewhere you have to run in unconfined territory. You have to break free of what's already there.
Applying this to your brand: say something different, look different, act different, be different. Change.