DIY and you will never have to worry about coil killing juices again, LOL. Well you might wind up creating some but if for sure gives you more options.
My least favorite coil killer juices tended to have freaking.... Food colorant in them which is 100% not necessary and a bit frustrating on the coils.
Thing is, it's also different for different tanks, coils, vapers and even vaping styles (length of inhale, using TC or not, especially if chain vaping) so yes, dark sweet and gunky (think NET juices and whatnot) will kill a coil faster in GENERAL but it's very hard to predict what will affect what, in vaping and etc.
Anna