I am curious to know how the progression through the ranks happened and how long it might take to get from a Lieutenant to a Colonel, for a infantry regiment and a cavalry squadron.
Also would all the officers be of noble birth or would i be able to raise through the ranks, if i were the son of a wealthy merchant, business owner or land owner (but not a noble). Although i imagine that if i were a non-noble, it would be easier to raise through the ranks of infantry, than does of cavalry, right?
From what i can tell, the purchasing of commissions was far a more extensive practice in the British army, then the armies of other nations.
I talked a bit about it here and here at least pertaining to British officers.
The French, Austrians, and Prussians really preferred nobility in their officer corps but the French were really one of the only ones to actually push for it. They would remove officers of lesser houses or middle class families if one from a noble house wanted in. The officer corps of the French army mostly came from the long established aristocratic noble families that could trace their heritage for decades or centuries. The others less so. The British army did not require a noble to be officer, some came from middle class merchant families such as Banastre Tarleton and John Andre. That being said, it was still a rank of privilege and reflection of some amount of wealth. Commissions were expensive and the life of an officer would be a pretty penny as well. The Austrian army had a more fair approach with their officer corp and did not really put many barriers, allowing those that had the ability and exceptional skills to rise to high ranks. Gideon Loudon is such a case for the Austrian army.
It was nigh a universal practice to buy commissions or promotions in most European armies. Not just British but French, Russian, Austrian as well. Each promotion had a cost to it, higher than the previous rank. The only rank you could not get as a commission would be the general positions as only the war office, ministry, or sovereign could award those. So one could buy up to colonel and that is it. Promotion could take awhile and was not guaranteed. Within a regiment or even at the company level you may have others vying for the same spot. It revolved around the seniority within the company and the officer next in line for that promotion. If a captain died, a lieutenant from the company would usually take his place if he could afford the commission. If no one in the company could afford it, only then it'd go out into the rest of the regiment. If not there, then it'd go out to the army to find someone to fill it. In peacetimes, of course, an officer would have a harder time finding opportunity to be promoted. War offered a better chance. Officers dying in battle, disease, illness, or age gave the rest a chance to get that position.
Rising through the ranks, if you mean from enlisted, to officer levels was difficult. In one of my previous answers I talked about it. However, beginning out as a lower officer would give a better chance. Banastre Tarleton began his service as a cornet (equal to ensign in the infantry) in the cavalry and later became major and then lt. colonel. Climbing through ranks in the cavalry did prove harder since one would have to have the skill as a rider and to afford the cost of caring for the horse, but rising from the ranks in the infantry proved difficult too.
Sources
Christopher Duffy The Military Experience in the Age of Reason
JA Houlding Fit for Service