The requirements and expectations for drug testing vary quite a lot from state to state. In some states and industries, the employer can force testing with no notice, but the courts are only OK with this when a real danger to lives can result. You can also be forced to take a drug test immediately in most places if you have a vehicle accident, a violent incident, have a medical emergency, etc.
Whenever they want to, the can do surprise ones to
It is a brand of "gag gift" that is actually clean urine. It would be illegal to use that in a legally sanctioned drug test, however.
An employer can legally test you for any drug they feel like testing you for, if the lab they send your sample to is certified to test for it. (Labs have "testing menus" that list all the things they're set up to test for.) Given that, I cannot imagine wanting to smoke actual aromatic incense - the stuff they sell at the import market you burn to make your house smell good. The product you are probably referring to isn't aromatic incense, it's synthetic marijuana.
legally no, since no one knows about it. Morally, yes.
No, a drug test will give results for drug use in the present.
If you smoke meth, it will show up on a drug test. The way to pass a drug test is not to use drugs. Not smoking all the time will just make your drug test ... test positive for drug use.
it is a drug test by mouth. they swab the mouth to detect drug use in the last 24 hours.
Depends on the type of drug test and the amount of time between your last use and said drug test.
urine test
Saliva test
saliva test
A drug test won't be able to tell which brand the drug is, just that the drug is present, and how much of it.
depends on the drug screen they use. if it is just an opiate test it will show positive for opiates and provided you are legally getting hydrocodone you will pass,but if its a more specific test it most certainly will show the difference. In which case you will fail.