hey no problem man were all here to help and learn!
damn that is some expensive Arimadex! lol i would hope its not generic for that price, but if you look around (and up at Eclen's banner

) you can find generic arimadex, aromasin and nolva and leave with a heavier wallet...
Half-life; the best way to explain this is with an example. The half life of a steroid depends on the ester that is attached to it. The length of the ester determines how quickly the steroid is released into the blood and used. So, using testosterone Enanthate as our example, which has a half life of 14 days;
Injecting 250mg, after 14 days it will have released HALF of the test into the body or 125mg, after another 14 days it will have released HALF of that or 62.5mg, another 14 days and it will have released HALF again or 31.25mg...
It takes time for the body's enzymes to break the ester from the test, and make the test bioavialable, this time depends on the length of the ester... here are some average half lives for esters;
Acetate = 2 days
prop = 2-3 days
Enanthate = 12-14 days
Cypionate = 15-16 days
Undecylenate = 14-15 days
Decanoate = 15-16 days
So- if you inject a steroid with any of these esters attached, after the number of days listed next to it you have had HALF the amount you injected still unused. After about 4 half-life cycles the compound is considered to be cleared from the system.
These esters are the reason why some steroids take time to show any results, we have to wait for overlapping injections to amount to a blood homone level concentration that causes a result. let me know if this isnt clear!
as a side note- you trainer talking about "withdrawl symptoms" from a steroid is absurd. If he means having your natural testosterone shut down then that will happen regardles if you pryamid a dose or keep it stable.