How many bottles of eye drops should I order?

Start from the directions: Apply 1 drop 3 times per day in each eye. Six drops a day, in total. Exactly how long a bottle lasts depends on drop size, which varies, but at that dose a .33 fl oz (10 mL) bottle runs out in weeks, not months.

The shipping side

Shipping is a flat $10.00 for one or two bottles and free on 3 or more, so the cost of getting each bottle to you falls as the quantity rises. The buy panel starts at two bottles; that is a default, not a minimum.

A rough way to decide

• One bottle if you are trying Quell for the first time.
• Two if you already know you will keep using it for the next month or two.
• Three or more if you use it daily and want free shipping.

Don’t overbuy

Spare bottles need the same conditions as the one in use: Store between 15° to 30°C (59° to 86°F). Only unopened bottles can be refunded, within 30 days of delivery. If you are torn, two is a sensible middle.

The buy panel shows the delivered price at every quantity, and how long a bottle lasts goes through the arithmetic.