We demonstrate from a system design perspective, that nonlinearity can be exploited, to minimize the impact of system margins on the system performance, both for point-to-point links and elastic optical networks. A nonlinear interaction causes a 2 dB reduction in launch power to be reduced to <0.25 dB signal-to-noise ratio (SNR) penalty and likewise, a 2 dB peak-peak (pk-pk) perturbation to the output power of an optical amplifier incurs <0.25 dB SNR penalty (for 5, 10 and 20 spans). Extending this to a gain ripple of 1 dB pk-pk with an internode spacing of 5x80 km, 10x80 km and 20x80 km the penalty is 0.4 dB, 1.5 dB and 5.1 dB, respectively, with pre-emphasis reducing this to 0.01 dB, 0.3 dB and 1.2 dB respectively. In elastic optical networks we consider the nonlinear relationship between SNR, margin and the fraction of capacity available. We consider scaling internode distances of a 9-node German scale network (DT9) such that the initial network diameter increases from 1,120 km to 6,720 km (six-fold scaling). We generate 1,000 different topologies based on the scaled DT9 node locations to quantify the impact of margin. For the unscaled DT9 network a 3 dB margin results in, on average, a 21% reduction in network throughput, however when the internode spacing is increased six-fold to a continental scale network, the network throughput is reduced by 40%, on average, for the same 3 dB margin.