Whats your experience with redosing?

I have some powder thats landing tomorrow, this will be my first time trying, but ive tried most opioid classes before. Ive been hearing that redosing is not effective within 6-12 hours because your enzymes stop being able to metabolize it, similar to codeine. Can anyone share their personal experience? I just want to know what my dose should be because I know my fiend ass is gonna want to redose after 2 to 3 hours or so throughout the night. Thanks guys