This is just my opinion, and it's not based on any kind of comprehensive study, but: I think that most people will not ever hit true plateau as long as they stick to a plan that limits their caloric intake to fewer calories than they burn, averaged over time.
That doesn't mean that you won't see periods of several weeks where there isn't any apparent weight loss. And it doesn't mean that you will always lose weight quickly.
But if you stick to your plan with patience and perseverance and diligence, then over time you will lose the weight you want to lose.
True plateaus - periods of longer than, say, 6 weeks when someone has stuck to plan and still not seen any loss at all - are, I think, extremely rare.
Very frequently, people cry "plateau!" when they have not seen any loss for just a week or two (common case of fat loss masked by fluid retention) or when they have been mostly but not entirely on plan. That makes plateaus look a lot more common than they really are.
High weight: 275 (August 2009) *** Low weight: 155 (October 2012)
Today, working off a partial regain. Current weight: 179.
* Make the best choice I can make, with every choice.
* Remember that the temptation in front of me is not the last of its kind that I will ever see; say "I'll pass today."
* Say "no!" to my whiny inner five-year-old.