Just chiming in to say, while this is mostly true, it is not always true.

I had a stint of about 2 years of job hopping every 3-6 months at the beginning of my career. Worked great for me every time.

The trick is to get the new job while you still are employed, not quitting and then looking for something new. Employed = attractive to other employers, but still a bit of a red flag. Unemployed = just a big red flag.