how long is bad for authority sites?

I am having a hard time finding a good domain for my next project.

My main kw is 8 letters long. I found this 12 letter long domain .. where first 4 letter rhymes with next 4 letters (and a good match from meaning) .. last 8 letters is my main kw. Would this be a goodname for authority standoint?

I can also add a single letter infront of my 8 letter kw and try to brand it .. like xtraveltips .. and try to brand it as expert travel tips .. or its a bad idea?

So how long is considered bad to you when you need an authority name?

Some major authority sites have 10-14 letter domains.

It doesnt matter how long it is once it rolls off the tongue.

The shorter and easier to memorize, the better, but I would try to keep it below 10 letters.

You need to worry about creating a solid brand. As mentioned above, some brands are proper long, but they are still succeeding; not everything is about finding a super short name; yes it helps, but you can still get a long name and then just get the first letter of each word.

this is some 24 letters bullsh!t XD

The shorter the better.. And a catchy one is also good..