I specifically got a Nissan for the company's reputation for reliability, and I intend to keep owning Nissans for a while. I'm in a 2002 Sentra now, and have my eye on a roomier 2008 Altima (there will hopefully be strollers to fit into the trunk in the next three years or so).
I guess that's the big debate - I know I could easily drive the Nissan for another 3 or 4 years, but then the market might be worse for buyers, my resale value drops, and I risk being the statistical anomaly that needs major repairs before 100,000 miles. Then I might be stuck making a purchase decision in a hurry (I live in LA - going carless ain't an option).
I've already had one big repair with this car - last year I blew my whole holiday bonus on a shiny new head gasket (a $1500 repair). Plus, I've had my share of run-ins with various poles and walls, so making it feel new again would cost more like a few grand (and involve a new rear passenger door
I don't hate the car, but I am kind of sick of it. But, wanting something shiny and new simply because it's shiny and new is SO not my style. I will make this purchase only when I've concluded it's a smart money decision.