British officers could rise in rank either through seniority or by purchasing rank. In wartime many commissions were issued without the need to buy them, and the high mortality rate among officers led to rapid promotion among the survivors. During long periods of peacetime, on the other hand, there was a return to promotion on the basis of years of service or purchase, for those who could afford it. This method of obtaining rank was severely criticized throughout the nineteenth century before being done away with once and for all in 1871. One celebrated case was that of a poor captain who had 47 years of service and had been in the Battle of Waterloo finding himself under the command of a rich lieutenant-colonel who had been only two years old at the time of the famous battle! Towards 1840 a lieutenant-colonel's commission cost approximately £7,000 - a small fortune at the time. Most officers could not pay such an amount; promotion by seniority was their only option.
In the infantry and cavalry in the eighteenth century there was virtually no academic training. The profession was learned in the regiment through contact with experienced officers, a system that generally produced a remarkably competent officer corps. 
However, the need to establish a military college was becoming increasingly clear during the Napoleonic wars and in 1802 the Royal Military College opened its doors at Great Marlow, moving to Sandhurst 10 years later. Edouard-Alphonse d'Irumberry de Salaberry appears to have been the first Canadian cadet admitted there, in 1807. Officers in the artillery and engineers could not purchase their commissions and had to attend the Woolwich Royal Military Academy, founded in 1741, for in-depth technical and scientific training. Canada had no academy issuing officer's commissions in the regular army between 1760 and 1876.
Because their regiment's stay in Canada was temporary, British officers, like their soldiers, did not form lasting links with the people of the colony. Without exception they lived in barracks built specially for them; their servants, called "batmen," were soldiers, and generally speaking the regiment was their society. It consisted essentially of a group of bachelors, because only a quarter of them got married - nearly always to British women of their class. One of the duties of regimental colonels was in fact to discreetly ensure that young officers did not enter into ill-considered liaisons. Marrying a woman from the colonies was tacitly prohibited. Every officer who did so was forced to leave the army. They socialized with the families of the colonial elite at balls, the theatre and dinners, but these cordial contacts would remain superficial. In Quebec City between 1760 and 1836 there were only about 30 marriages between officers serving in British line regiments and Canadian women, nearly all of British descent. It is not surprising, then, that many young women of the colonies were deceived by these gallant young men in uniform; such occurrences were even the subject of poetic duels published in the Quebec City press.