The understanding of the accretion processes on to compact objects in binary systems is an important part of modern astrophysics. Theoretical work, stemming from that of Ghosh & Lamb (1979), has made clear predictions for the behaviour of such systems. Such predictions have been supported in a general manner by observational results of considerably varying quality from galactic accreting pulsar systems. In this work a much larger homogeneous population of such objects in the Small Magellanic Cloud is used to provide more demanding tests of the accretion theory. Data arising from 10 years of weekly X-ray pulsar monitoring with RXTE are presented & combined with even more extensive optical coverage from OGLE. The results are extremely supportive of the theoretical models and provide new insights into the manner in which accreting pulsars behave and evolve.