What are the best uses for political influence?

[Jor1994]

I can't really see much to use it on bar stability. Everything else seems very situational, like founding cities or getting claims. Is there anything consistent to use it on.

If it's the province investments then what are the best ones?

[Menkerot]

Depending on your needs, but new slots for buildings and trade routes are always in demand, and in case of a specific region you want to fortify past level 3 fortress investment can be viable. Only population one isn't that useful.

apart from that, cities, holy sites and such already need a lot, plus new laws. And upping stability is already a huge deal.

[galadon3]

Depends wholly on what you want and what your realm needs in its situation.
If you are in greece you might not need to found cities, if you are uniting the britania you might need a ton of new cities.
If you want to expand fast militarily you might need a ton of claims, if you expand diplomatically and don't do much military expansion you wont need those.

Province investments are hardly ever really worth it, IF you fullfill missions you might need them sometimes, otherwhise more traderoutes in the capital to get more empirewide tradegood-bonusses, but even that is rather limited since the costs mount up quickly and influence is needed for a lot of pretty important stuff.

[Jean-Maurice Nya]

1. Cities
2. Divine sacrifice
3. Claims
4. Province development for either more buildings, either bigger fortress limit (if you don't have enough from military tradition). More pop is better through tech and trade routes from nobles and citizen.
5. Wonder
6. Deify ruler

But as mentioned it'll depend on what you want to do and at what stage of your run you are. And depending on your priority, seek the related tech that decrease the cost in PI.

[shoobers]

If you're running over 100 PI and can't figure out what to do with it, you might not be investigating your internal concerns much. Influence, not gold, is a major bottleneck.