Hi Ney!
The answer is yes and no
Scenarios have a turn limit, but when this arrive and the scenario ends (and you win or lose) you can keep playing on as long as you want
But of course, after the end turn there will be no more historic events, scripted reinforcements and the like
In my opinion this feature is cool if you want to keep playing for a bunch of turns to maybe end that "master offensive plan"
you had but couldn't finish before scenario ends. But keep on playing for years would seem a little pointless to me
NCP has a dozen of medium length scenarios (from 20 to 40 turns maybe), a bunch of introductory ones (4-6 turns) and a superlong scenario (Peninsular Campaign) that is 300 tuns long
, but played only on the Iberian peninsula.
ACW has a full war campaign (+100 turns) with several variable setups, advanced start campaigns (1,2, or 3 years into the war) and a bunch of small and medium battle scenarios.
WIA has 3 long full war campaigns (70-100 turns each aprox):the 1755 French and Indian War, 1775 American revolution and 1812 British-USA war.
And besides about a dozen short an medium length scenarios dealing with parts of those campaigns or other minor wars (Indian wars mainly).
As you see there is a lot of play in any of them!