That is another issue, which is that the conflict between using seasonal and yearly turns. In my opinion, seasonal turns are much more realistic, but I can how the issue of time can be hard for some players. In STW, 16 years, the age of an heir coming of age, is 64 turns, and the life-span of a king can stretch over 200 turns. Also, lots of people had a hard time thinking around the idea of income coming in every 4 turns, not every turn.
If a game was seasonal in turns, then certain units, and I do mean only certain, can disband automatically, but if it is yearly, then I would not want it to be so, for the armies which could have taken years and years to building up correctly (due to other flaws of the strategy map) will have a very short shelf-life, and it is not going to be popular if you build up this great army and suddenly half the men "get old." That is a sure way to turn people away from the game.
Myself, I want three things to be different next game. Instead of a county/province production screen, I want it so that every building in a province has its own production queue. so instead of only one unit at a time being built in a province each turn, you can rig it so that at the bowyer, one archer is building, at the swordsmith, a unit of swordsmen, at the horse-breeder, some hobilars, and at the spear-smith, an armoured spearmen unit, and after one turn, ALL 4 units appear at once in the same province during the same turn (if their production times allow). This way, it is on a more realistic timescale to build armies.