Renormalizable theories can be extrapolated to high energies
The main feature of renormalizable theories is that their physics may be extrapolated to and remains well-behaved at arbitrary high energy scales – or at least up to energy scales that are exponentially higher – e.g. \exp(1/e^2) times – than the typical scales in your theory. Because of that, any contributions of new particles or, more generally, new physics at these extremely high energy scales Λ are suppressed by 1/Λ^k where k is a positive exponent.
— Regularization and renormalization
— Lubos Motl
2013.05.25 Saturday ACHK