Be aware that racial level caps won't increase from game to game so if your non-human characters reach racial level caps already in PoR they'll be useless in later games.

The beginnings will be more challenging if you start the games with freshly created characters instead of imported ones but in the end it only will save you some grinding. You will have more level ups in CotAB and SotSB if you start them with freshly created characters, this doesn't apply to Pools of Darkness where you won't get close to the level cap without grinding.

Cool thank you both for the info. PoR is fun enough that I want to keep exploring regardless of XP. Plus I'm guessing you can still gain quite a bit of XP even after you hit the cap but you just can't train until Curse.

There's one rule about that to be aware of: If you have enough XP to gain more than one level, you will only be allowed to gain one, with your XP being set to 1 less than what would qualify you for another.

This actually leads to what I consider to be a rather significant game design issue with Curse. In that game, you ca dual-class for the first time; however, the game throws you, right away, into a dungeon that you can't just leave, meaning there's no way to train. As a result, if you dual class at the start of the game (which many players will tend to do, seeing as it's the first opportunity to do so), they'll be stuck with a level 1 character for a while, and a lot of the XP gained (perhaps most) will be thrown out on that character. This can be very frustrating for a player, to the point where I consider this a design flaw.

From what I hear, there's also an issue in Dark Queen of Krynn, where you can't return to town to train in the later stages of the game, again resulting in wasted XP.

(I hear something like this happens in Pools of Darkness, but at least there the player has has the ability to dual-class in the previous game, so it's not as bad.)

(Worth noting: The Infinity Engine games do not implement this rule (which leads to an exploit in Icewind Dale 2 due to the broken way XP rewards work), but Temple of Elemental Evil does. Then again, the games mentioned here allow you to level up anywhere, unlike the Gold Box games where you need to find a specific place to train.)