I sniff every 1/2 hour approx, one good pinch in each nostril, but the frequency depends a bit on the type of snuff, with heavily scented snuffs usually it takes a bit longer since I feel satisfied with the lingering aroma even when they can be low on nicotine.

With fine and not heavily scented snuffs I tend to pinch more often but with smaller pinches, it helps to maintain the aroma fresh in the nose.

The quantity depends greatly on the type of snuff, with fine & dry snuffs a small quantity goes a long way so maybe 1 g per day, with medium nicotine moist snuffs it ramps to 3 or 4 g per day.