What can I do to keep army tradition up?

[Spikee78]

I have a lot of active forts to keep up already, I can't keep building some (and I think that has a negative effect on the modifier anyway).

What can I do?

The modifiers that change the value are there, but I mean, what can I do best to keep a positive modifier?

 

[bbqftw]

Dismantle your forts and use it to buy mercs to invade people

You need massive investment to keep good AT while playing passive (looking at 2++ idea groups)

cheaper just to get it through sieging

 

[Pelthis]

Yup, the best way to gain shitloads of AT is actually going at war, doing battles and sieging forts. If you stay at peace, no matter how many forts you have, it will decay. You can pick some military ideas who prevent decay (there is one in defensive and another in aristocratic IIRC) but the best way is still killing people wherever you can.

 

[Zephyrum]

Quality/Defensive ideas give +1 army tradition.

Aristocratic gives -1% decay.

Keeping enough forts can give you up to +1 army tradition (super expensive though - one fort of the current technology per 50 development on your nation).

If you're REALLY REALLY desparate, Aristocratic-Espionage gives a -1% decay policy.

Theoretically speaking, with (all of) these modifiers, you have zero AT loss over time, but keeping up a policy is expensive, this requires 4 complete idea groups (3 of which are mil, so if you're doing with group limits you need 5 unlocked), of which one is absolute trash (esp).

You're better off just invading stuff and keeping it up by warfare, honestly.

EDIT: Unless you're a very tradition-based nation. Prussia and Shimazu both get +0.50 AT and -1% decay. For these, just Quality/Defensive keeps them stuck at 50% AT and can sustain up to 70% before getting actual decay. If the money influx is pretty massive, you can use forts' +1 for a natural 70% and a sustained 90% without decay.