A study of Shareshull's achievements in law enforcement must not overlook his persistent activities in holding the land assizes, fully documented by huge rolls still in existence. Since land cases make up so large a proportion of all law cases in the fourteenth century, it is inevitable that a distinguished judge like Shareshull should have given a correspondingly large proportion of his time to the circuits of assize on which he acted, the north-western, the south-western, and Oxfordshire and Berkshire, usually included in the latter. His work as a justice of assize was vitally important. It necessitated incessant journeyings at certain seasons into far-distant regions; it also involved intricate problems of land law as is proved by the number of assize cases begun before him on circuit and brought into common pleas or king's bench, or adjourned to Westminster before himself and his colleagues.

But it is of course true that the taking of land assizes by Serjeants and judges of the upper courts was so much a matter of routine that it represented nothing unique in Shareshull's case; nor did the pecuniary advantages to the crown bulk large either in real actions before justices of assize or even in the formidable Quo Warranto proceedings before justices in eyre. Rather, it was in the maintenance of law and order and the enforcement of the new statutory regulations on economic matters that the great opportunity came for the profits of jurisdiction. Further, although the conviction or the flight of felons meant the confiscation of their chattels by the crown, on the whole it was the amercements and fines for trespasses, either common law or statutory, that were the veritable gold-mine: large sums, often beyond belief, from the great offenders, particularly the ‘ ministers’ of the king; small sums from innumerable petty offenders, especially from those found to be infringing the new economic legislation. These distinctions will help to make clear the significance of Shareshull's judicial work and to explain the changes in its character at successive stages in his career.

By the accession of Edward III Shareshull had been busy in the upper courts for several years as a serjeant-at-law, and had served on a few special commissions for which unfortunately no proceedings seem to have been preserved.