Hello Aleksey
Bear in mind that in Russia, as in the rest of continental Europe, but unlike Britain, all the sons of say, a Count, were Counts, their sons were Counts, and so on. According to another thread, there were, for example, about 150 Princes Golitsyn. So you could quite easily have a young Count X, with title and splendid ancestry, but not much money, and distinctly worried about being posted to the Standart because of all the expense.
In Britain, by contrast, only the eldest son inherits. So, the 7th Duke of Marlborough had two sons. The elder became the 8th Duke, the second was Lord Randolph Churchill, whose elder son was simply Mr Winston Churchill (though he was, for a time, the 8th Duke's heir between the death of Lord Randolph and the birth of the future 9th Duke).
Ann