I play within the confines of the game. All my sims have some measure of realistic type gameplay - some type of job or way to make money, family, chores, etc. Other than that, if it's in the game, anything goes. I don't typically cheat unless something goes screwy in the game, and I don't add outside gameplay that isn't needed other than MCCC and its story progression (and a whole lot more). Especially lately, I've been obsessed with Super Sims/Ultimate Sims...not very realistic, but hey, totally realistic in the Sims World! Realistic to me is if it can happen in real life - and there are people like that out there, though not with EVERY skill known and every job etc.
I just play the Sims, man.