Is it worth worrying about branding principles (name, logo, slogan, etc) when launching your app? Or should that come afterwards once you get some customers?
One issue is that renaming a company later on or getting a different domain name would cause confusion with the original customers.
I agree with SEO National. It does matter, and you should definitely pay attention to it. You can't just ignore it.
But like every other aspect of a startup, there's a fairly high chance of getting some part of it wrong. Just pivot and adapt, like every other aspect of your startup. And yes, sometimes that means renaming and/or picking a new domain name. Yes, some customers might get lost in the mixup, but if you do it right (keep the old domain name and redirect it, send out an email announcing the change, etc.) it will be minimal. Remember that you're changing it because something about the old way was having an impact on getting and keeping customers, the new way will (hopefully) work better, and if you lose a few customers, you should be able to make up for that quickly.
I wouldn't stress too much about that particular point. Many businesses have rebranded themselves without any problem.
I Truly think that branding is important through the complete building process. Branding can bring a sense of who you are to the customer and can make a difference on if they buy or not. Just get the basics down, logo, slogan, colors and font. Then make sure what ever you do you carry these the same in all future happenings.
The brand is you and your values its best to show them from day one!
However i agree with the above also never be scared to adapt later. You must adapt to survive!
Although I can't back my answers up with proof - since I'm still in the development stage of my business..
However, I have pitched my idea to a panel recently and they picked up on how effective my branding was, since then it has been something I've always tried to incorporate a decent branding strategy.. First impressions mean a lot and if your branding is something that can stick in head of whoever you are showing, that's got to be a bonus, right?