Do you ever have a hard time deciding on the rules for a character concept?

[The Pale King]

As the title says, I often come up with a concept for a character before the rules that will represent them on the table top, but I notice that my concepts often have little to tie them to a class, or a set of skills, or even a race. Does anyone else have this difficulty? How do you decide what rules to weave into your background concept?

[Isonaroc]

Sorta, kinda, not really. I'm pretty familiar with at least the fundamentals of the system, so when I'm creating a concept I'm usually (consciously or not) identifying how it'll work in the rule set and tempering it as necessary to work.

[JosMartigan]

I do that ALL the time. I create an image of a character in my head and the rules/available options always fall short of helping me create the idea I want.

[PossibleCabbage]

I play and run a lot of different tabletop RPGs, so generally when I come up with a concept that doesn't work well with one system (e.g. Pathfinder), I can file it away as something that might work better in a different game. I just tuck character note sheets inside the covers of the core rule books for the various games.

[Dragonchess Player]

Is it because the concept is general enough that several classes/multi-classed combinations can fit, is so specific that the existing rules have a hard time modeling it, or what?

There are enough options in classes, archetypes, prestige classes, and feats that most concepts can fairly well realized (maybe not immediately at 1st level, but within a few levels).

[Drahliana Moonrunner]

I use the concept to find a general class package. Then if neccessary, I alter the concept to fit.

Being flexible in your concept is the key.