I you train heavy regularly, you train abs. Unless dieting for a show, or if you have shallow crappy abs, I don't bother training them specifically. Just makes my workouts even longer.
I usually don't train them at all. With the program I'm on, about every other month I'll hit them 1x a week for 3-5 sets of 8-15 reps. That's a lot of ab training for me, lol.