Addiction - low dose of heroin

[mullet0224]

I know withdrawals can start after "3 days of sustained use".

SWIM and his girlfriend have been splitting a dub of black tar (a dub here is like .3) every day for about 2 weeks
they smoke it
every friend they know that is a 'junkie' uses considerably more than that every day.

does anyone else use such a small dose, and do you experience withdrawals when you stop using that amount?
tolerance starts to call for more sometimes, but this is all swim can afford. and swim feels fine using this tiny amount. so if he stopped tomorrow would he experience painful withdrawals?