Titles can be inherited and go on for life, passed down to oldest son. Some women can inherit titles and get the perks too, if there is no older living male relative that is closer. In 1963 these women were allowed to sit in Parliament The King or Queen can grant titles, too, some for life, which means after they die, nobody inherits the title, or can make a new title, to give the person's kids something to look forward to.
Second or third sons just usually get referred to as My Lord or the girls sometimes get My Lady, but depending on whomever they marry, they might lose the title or gain the guy's title. Most female titles are easily obliterated.
I personally think that part of the deal sucks.
The highest title is obviously Duke and there aren't many of them. Well, in historical romances, the place is always full of 'em, but not in reality.
Nobility in other countries is slightly different as you could expect.
They are not all rich.
Some of them actually have to work.
The oldest son gets absolutely everything but usually can't sell any of it. So he can be very poor, lose his land, but retain a title.
Some titles can be purchased, as it the case in my book, Kisses to Go. And believe me, I looked that up. The very oldest titles, as in the case of this story, can be sold. There are even listings of prices for titles available for sale right now. Of course, the higher the standing, the higher the price.