Cobb: We need the heir of a major corporation to dissolve his father's empire.
Eames: Well, you see, right there you have various political motivations and anti-monopolistic sentiment and so forth, but all that stuff is at the mercy of your subjects own prejudice. What you have to do is start at the absolute basic.
Cobb: Which is what?
Eames: The relationship with the father.
Eames: You mustn't be afraid to dream a little bigger, darling.
Arthur: With the slightest disturbance, dreams are gonna collapse.
Cobb: Dreams feel real while we're in them. It's only when we wake up that we realize something was actually strange.
Cobb: What's the most resilient parasite? An idea. A single idea from the human mind can build cities. An idea can transform the world and rewrite all the rules. Which is why I have to steal it.
Cobb: Never recreate from your memory. Always imagine new places.
Answer: The story really doesn't imply too heavily exactly how long Cobb has been on the run. Very few clues are given, so it could quite plausibly be less than a year since his wife's death, in which case their children would not have aged dramatically. Their voices on the phone seem compatible with children of the ages shown at the end of the film and Cobb shows no concern when reunited with them that they should be older than they are. Two sets of children are listed in the credits, of different ages.
Tailkinker