Depends on the incense.
Some of it you can inhale copious amounts of before feeling sick.
And some you only need to inhale a little bit of before feeling like your guts are rebelling.
Did you hear how that is hazardous to priests' and church workers' health now? I think Rush was talking about it today, but since I can't listen from here... I don't care, I always have dozens of candles going on all my altars.