Is Detox Worth the Trouble?

Hey, to save you the time, I'll make this short.

In just under 3 months I'm going to be moving out of my house to college, but suspect that my parents might drug test me when I come back to visit because I've been caught once about 5 months ago.

I smoke about every other day, and was just wondering: If I'm in college, and know I need to come back home in a few weeks, should I even bother dropping the money on a detox kit, or should I just exercise and drink lots of water?

I ask because everybody's advice towards somebody facing a drug test seems to be "DRINK WATER, SWEAT IT OUT." and not "GO GET THIS DETOX."

Post Script: Do detox kits even work? If so, which one's best?

I would buy the Quick Fix synthetic urine, thats what I did. Just make sure your parents don't watch you.