Maybe you're tired of recharging so often. Maybe you notice a rapid drop-off in vapor quality or quantity. Maybe you'd like to try an atty, carto or tank that's not compatible with your current e-cig. Maybe you found out that the only cartos compatible with your unit are adding up in terms of expense. Maybe your costly batteries are wearing out too often. Maybe you want to try a low resistance carto for more and warmer vapor without overheating and burning up your cartridge or consigning your battery to an early grave. Maybe you just don't consider yourself a smoker anymore, so the idea of looking like you're smoking an analog no longer appeals to you. These are just a few reasons people decide to move along.
Here's the typical progression:
1) E-cig that looks like a cigarette. Small battery, sometimes proprietary cartos that don't allow refilling or proprietary threading that don't allow other refillable cartos to be used. Many have automatic batteries and a LED on the tip to appeal to newbies. This class also doesn't let you use low resistance attys and cartos, since those should only be used on batteries over 450mah or so.
2) The eGo type. Roughly the size of a Sharpie marker, these mimic the form factor of the original Joytech eGo but are now produced under different names, by different manufacturers and in a variety of capacities. All but one are sealed battery units, therefore disposable. They will last from a few months to a year or more, depending on capacity and your vaping habits. Currently, they are available from 650mah up to to 1300mah. This is where the automatic battery idea is dispensed with. Some of them have lights, but they're usually at the button and sometimes perform other functions, such as the Firefly's battery condition indicator, which is located in a ring near the bottom of the unit. These all have much higher battery capacities than the stick or analog look-alikes in #1. Their voltages are usually regulated from 3.4 to 3.7V. They're a good introduction to high quality mods. They can be used with many kinds of tanks, cartos and attys, including low resistance attys and cartos, as well as those specifically designed for them. Some models are the eGo, Riva, kGo, GoGo, Vgo, Firefly and one that takes generic batteries, the E-Power. For someone "graduating" from the mini or analog look-alikes, my personal recommendation is the E-Power for it's replaceable switch and use of easily available generic replacement batteries.
3) Mods: Some people never bother with this step and are perfectly happy to stay at #2. Others skip #2 and go directly to this category. In terms of variety, this is where the vaping world really opens up, so you'll need to do your research to find one that fits you the best. Mods include all those devices, either tube or box shaped, that take one or more non-proprietary batteries. You'll find mods that take very high capacity, high drain batteries of all sizes. They are compatible with the maximum variety of cartos, atty's, tanks, etc. This is also the place where you find the bottom feeders, top feeders and all those beautiful wood PV's like the Reo, Monekyboxx, etc. This is also the point at which a multimeter becomes virtually indispensable.
4) "Super-Mods". This is the category that includes the variable voltage mods, the high dollar mods and all those mods that appeal to people who love to tinker, experiment, try different voltages, etc. The Provari and Darwin are two VV mods in this class.
I don't know what options you have with the V4L. If your carto is getting too hot, you might need something that can keep up with you and won't overheat. So you might want to look at moving to #2 or even #3. You'll have a very large selection of cartos from which to choose. I chain-vape and never have a carto get uncomfortably warm.
