How long does it take for you to get THC out of your system?

I've been doing research and have been reading other sites about how long it takes for THC to get out of one's system. To my understanding, the rate at which THC is expelled from one's system (via urine) depends on their weight, level of body fat, speed of metabolism, potency of consumed cannabis, among other variables. 
 
I'm 5'10 and about 165 pounds, The last time I used my vaporizer was on 10/7 at midnight, and it is now 8 PM on 10/10. I workout roughly every day, but not strenuously. I do daily push ups and rode my bike yesterday. I have a fast metabolism. 
Prior to sunday, I had dollar home kits, and have been using those but the fact that they only cost a dollar seemed a little shady to me. So, earlier tonight, I went to CVS pharmacy and picked up a First Check home kit (around $18) and tested negative for THC. Although I got a faint line, it still counts as negative. Turns out the initial dollar testing kits weren't lying

Not entirely sure if this is true or not, but just to be safe, I've been taking 1 niacin pill and 1 complex vitamin B pill every day for the past 4 days, and I'm wondering if that may or may not have contributed to the reason I passed.Niacin stimulates the metabolism, so it only makes sense that it would help, but I haven't read any consistent information proving that theory. 
 
The other methods that I've read are:
-Using Certo with gatorade 
-Diluting the sample with lots of water or diuretics 
-Smuggling synthetic urine/friend's urine and using a handwarmer to keep sample at a decent temperature
-Taking cranberry pills
-Lots of running/exercise and sweating
-Visits to the Sauna
-Detox
Anyways, this thread is for other users to discuss how long it takes for them to rid their system of THC, also feel free to provide any information on how to pass a test (primarily urine). I'm not so sure with the other forms of testing, like blood or hair testing. 
 
LET THE PISS CHAT BEGIN!