To achieve longevity, you must reconcile the conflict between what you shoot for money and what you love to shoot. Ideally, you get paid to shoot exactly what you love to shoot, every day. Reaching this nirvana requires making tough choices, a careful business strategy and attention to basic business practices.
I’ve been saying this stuff for a while, but just in case it hasn’t sunk in yet, take it from somebody with a little more experience. Read the article by Doug Menuez.

“tough choices, a careful business strategy”
That about sums up why some photographers will never be successful.
They don’t want to make the tough choices and refuse to even think of a business strategy.
I’m glad that you take the time to point this out over and over again. It needs to be said.
Damien Franco
Hi Damien,
The way I ee it, too many photographers are willing to jump at any gig that comes their way, rather than concentrate on marketing and portfolio development to land the gigs the can really be passionate about.
The result? Mediocre photography and lackluster earnings. The portfolio of a generalist with no style or subject commitments is a truly boring portfolio.
A photographer’s primary differentiator is his style. Don’t look like everybody else. Pick a subject and a style and own it.
I get excited about music, nightlife, portraits, and creative advertising. Stick to what you love, and it’ll show, not just in your photography, but in your enthusiasm and customer service with clients.