This question can mean two different things: how long does it take to vape a bottle of e-liquid, or how long does a bottle last until it expires. I am going to answer both of these questions here today.
The time taken to use up a bottle depends on 3 factors. The first, and most obvious, factor is how much e-liquid is in the bottle. Obviously a 120ml bottle will take longer to vape than 10ml bottles. Companies make large e-liquid bottles so it lasts longer, with bottles usually up to 120ml.
The second factor is how you vape. If you vape a normal sub-ohm mod and tank with wattage between 50 and 100 watts, you are most likely going to vape around 30ml in an average week. If, however, you are a cloud chaser, you most likely will use 60ml in an average week.
The final factor is how often you vape on an average day. A casual vaper may last weeks with a 30ml bottle, but a chain smoker (who vapes constantly, almost without putting the device down) would vape a lot more.
If you look to see how these three factors apply to you, you should be able to work out how long your e-liquid will last before it's finished.
Like food, e-liquids also have best before dates, to tell you when the vape juice is no longer guaranteed to be the same quality. The expiration date depends on the ingredients involved.
PG has a shelf life of 2 years, and VG can have a shelf life of 4 to 6 years. Flavours can last up to a year, but the PG and VG (which are preservatives) make the flavour last longer. The expiry date is dependant on the PG shelf life, so e-liquid lasts 2 years. This is the same with all e-liquids, even Max VG, which still contains a very small amount of PG.
The expiry date can also depend on how the e-liquid was created. If it was made by professional chemists in a science lab, it will last longer than one being made in some guy's shed, as well as being safer and better.
E-Liquid can still last up to 2 years once opened, provided that the lid is firmly sealed and the bottle is properly stored.
Another thing that affects the shelf life is how the e-liquid is stored. The best way to make it last the full two years is to store in in a cool, dark place, out of the sun, as the sun can break down the ingredients. The best place to store it is in an opaque container in a cupboard or on a shelf, away from the reach of children.
There are two things to look for to see if your e-liquid has expired. The first is separation. Sometimes, the heavy elements will sink to the bottom of the bottle. Shake them up to mix them again. If the e-liquid doesn't mix, it's probably time to get rid of it.
The second thing to try is the smell. Like milk, e-liquid can change its smell when it expires. If the e-liquid smells off, it is most likely time to throw it away.
Like other foods, the expiration date is mainly a suggestion for when to finish the vape juice for. It is not dangerous to vape it, neither is it bad for your health, it is just a recommendation. Several things can happen to the e-juice when it expires: the taste can fade away, the smell and colour can change and the bottle can become tinted. The nicotine can also disappear, which is bad news for any former smokers wanting to get their nicotine. If these happens, you should probably throw it away.
There are many ways to get rid of your e-liquid when it has expired. Don't throw it in a drain without heavily diluting as the nicotine will end up in the watershed. One way to get rid of it is by pouring it in a suitable, absorbent material, like coffee grounds or kitty litter.
If you are a gardener, you can put the e-liquid in water and spray it over the plants, as pests don't like the nicotine.
If you find yourself constantly having to throw away e-liquid, try getting it in smaller amounts. Use the guide above to decide how much e-liquid you probably need.
Now you should know how long your e-liquid will last, so you can carry on vaping without worries of e-liquid expiring or running out.