Archon, combat experience  can be upgraded via the library. It can be really helpful if you are below 40-30 level and want to level up a bit faster. Using your scrolls of using for maximizing combat experience to meself is kinda useless. You should better focus on other things. Such as grain consumption,reduced unit training and if you belong in a coalition which hold pans, maximize the veteran ones! It's to little the xp to gain actually much more.Unless if you got millions of offense or def and you fight very often. It's a costly action and should be used on your earlier levels in my opinion...or not at all :)

 Archon, It increase the amount of experience points you get in a fight like defending your city, raiding someone, conquering/defending colony etc. The more experience you get, the faster you reach next level. The increase in experience won't change the amout of PvP point you will get in a tournament, just xps from fight will be increase.

I already made kind of lengthy answer in past, but can't find it anymore on forums

short answer is they are worth it, it cost scrolls, but since u will level up faster u get them back. they more effective on lower levels(meaning u get payout faster, talking in real time)

btw regarding forum:

1. what happened to search function? its useless, results shows from all plarium games not only from sparta

2. second I found at least 5 exactly same threads as this chap is asking, but they are in trash and unable to view for players(forbidden access)

3. we spent our time to answer and educate younger players, but I'm not going to repeat myself every week, they should be able to use search function to find answers for their questions, or we should be able to link to them answer...

i think battle exparience shoold be maxed first thing in this game follwed by the grain consuption 

Rob May said:

btw regarding forum:

1. what happened to search function? its useless, results shows from all plarium games not only from sparta

2. second I found at least 5 exactly same threads as this chap is asking, but they are in trash and unable to view for players(forbidden access)

3. we spent our time to answer and educate younger players, but I'm not going to repeat myself every week, they should be able to use search function to find answers for their questions, or we should be able to link to them answer...

Hi, Rob!

Yes, we are aware of these issues. Unfortunately, it will take some time to fix them.