I'm not sure how or why it happened, but it seems like all my civics are suddenly super expensive to enact. From my previous games I didn't remember "Artistic Expression" costing 12.1k influence. Is there a system that influence the cost?

Enacting cost (from a thread in Strategy Guides)   30+5*(Era^2)*(Number Civics Enacted^2)

Yeah they got increased in the recent patch. I think it's good though; there are plenty of ways to reduce the cost, and I just ignored them all before. Now if you want to pick a lot of civics you'll need to really invest in influence or take religious tenets or civs that give you cost reductions.

A civics choice is always cheapest to enact when it appears first time. In my first game, I enacted every civics right away. So I got the impression that all these civics are easy to make. In my second game, I just tried to save my influence points for empire expansion. When I remember again the civics things, I just found they are quite expansive to make judged by their effects, and for some of them I just give up to avoid the change in the ideology axis. It seem to be another example of "Tall vs Wide strategy" in the HK.

Thanks for all your explanations!

I think what happened in this latest game was that I had a tough start (only 2 territories surrounded by mountains and ocean) so by the time I started to get civics, I didn't have the influence to enact them which spiralled out of control and made it so I could never produce enough influence to match the ever increasing cost.

In the end most of the civics I managed to get came for free through events and osmosis events.

Formosa2077 wrote:

A civics choice is always cheapest to enact when it appears first time. In my first game, I enacted every civics right away. So I got the impression that all these civics are easy to make. In my second game, I just tried to save my influence points for empire expansion. When I remember again the civics things, I just found they are quite expansive to make judged by their effects, and for some of them I just give up to avoid the change in the ideology axis. It seem to be another example of "Tall vs Wide strategy" in the HK.

This is not actually true BUT they do get more expensive with each Era you enter if you look that the equation Krikkitone mentioned above, so if you wait too long to enact them they can get very expensive indeed. More details in this thread. You can also get up to 85% reduction by selecting certain civics, tenets and researching techs which makes a huge difference.

I think the main idea is that you are not supposed to have more than a handful unless you really go all out on Influence and that makes sense because you only want to enact those that synergize with your main strategy.

Ouch the formula ... 

Even if you really go all out on influence, your influence output will never evolve like 5 squarred era !

You really do not need it to evolve that much, currently along with Cultural Osmosis events there are also Society events (or at least that is how I call them) which let you enact one of the options of a specific civic. For example the event that has to do with Child education/labour.

During the Osmosis and Society events those changes cost 0 Influence. If you know the events and are ok with the choice they give you, you can easily enact every civic you have access to without going hard for Influence.