like bpdaddy said...it's up to you dude. right now, mid spring, i'm training abs one day, obliques the next, back and forth. i only spend a few minutes at the end of my workout doing one or the other. i have about 3 different routines that i rotate between for abs, and probably 2 for obliques. by 'routine' i mean maybe two exercises max with about 3 sets per exercise. i guess it's more of a pump routine than anything else. i find that it works at least psychologically. i am relatively lean, so my midsection definitely feels tighter when my abs are more consistently pumped. girls looking at my midsection could probably not tell the difference if i'd trained abs today or 3 days ago, but they feel better when they've been trained more frequently. i can definitely maintain ab definition and strength only training them a couple of times a week though. like the other guys have been saying, it's a choice man. do what works. for me, summer time is the time to keep my abs nice and tight because i never know when the occasion might arise when i'll be around some nice looking girls and they want to see a little somethin'. i'm in college so the possibility is always there, day and night. good luck to you bud.