Ok this is where I eat my words on earlier topics I had commented on.
I used to moan “ what is the point of these puff counters “ people always request on devices”
Mine was always at 99999 as id never bother resetting them as one comment I made before on a topic puff counters were like counting how many sips of coffee you get from a cup of coffee.
How wrong I was .
We were asked on here before how often do you change coils or pods ?
My reply was I used to change coils or pods on a weekly basis regardless if good or not and give devices a good clean.
But this meant throwing away good coils with plenty of life left but also meant I would never suffer the unpleasant burn out of coil.
So I changed routine to wait till I started to see my e-liquid change colour ( goes darker ) this is due to caramelisation build up and burnt cotton on coil or when tastes started to fade.
So I have evolved 
I now use the devices capabilities it’s why these developers work so hard and leave us vapers figuring out the little tricks.
I am a G man my main devices I now use is the Armour G I own 5 of them 
I like different colours to match the eliquid flavours I mostly use this eliminates ghosting from other flavours.
The pods are dark so can’t see if liquid is going darker
I reckon they are darker and not clear is to protect your liquid from light exposure.
So back to puff counter I reset to 0 on each coil change and after a few coil changes I noticed the lifespan of each coil is around 2400 puffs so I change my coils and clean devices every 2000 puffs
The gtx coils are robust and pretty consistent so I found I can rely on this technique.
And at 2000 puffs per coil means I now know I get 10,000 puffs per pack of coils.
So yeah I eat my words puff counters are awesome lol I now know why they are there.