Don't know when you should change your coils? We'll help you with that...
All atomizers have a coil that heats the e-juice or e-liquid in the mod until it turns into vapor. Sometimes, it can be difficult to determine exactly when the coils should be changed. There are a variety of factors that affect the life of the coils and how often they should be changed.
One of the first indications that it is time to change your coil is simply found in the taste. If you find that your vape is providing a burnt or unpleasant taste, more than likely you will need to think about changing your coil. If you are able to see your coil directly and you notice a dark or crusty color on the coil, that is an indication that you will need to change out your coil. In some cases, where you are able to remove the wick specifically (rebuildable atomizers), you may be able to just re-wick your device and continue vaping, however you should consider changing out your coil when the coil's lifespan between re-wicking is short and you find that you need to re-wick very often to obtain a pleasant taste.
Another factor that affects the lifespan of your coils is the juice you are using. Typically e-liquid with higher VG (vegetable glycerin) ratios will gunk up your coils faster. Also, flavors that are more deserty or more sugary can wear on your coils faster than less sweet flavors.
This video goes into detail about those various factors. Changing your coils whenever necessary will greatly improve your vaping experience and let you taste the all the amazing flavors that vaping has to offer!