I found that I kept getting nicotine in my mouth. Does anyone have any idea why this is happening? I would like to find out how to prevent it.
MVS is a great store
Carts w/Atomizers
With regular cart's and attys...you might try some other cart types/shapes. Some are round and blunt, and some have the fluted style mouth piece. There are also Smart Carts and LUCID carts that you might try.
Direct Dripping
If you haven't tried this...consider giving it a shot, as you said you work at home and don't mind stopping to top carts fairly often. Here is how to do it.
Take the atty off your battery and pull the cart off your atty.
If you are going to use a different flavor from your last one...blow really hard through the battery end of your atty a few times to clear whatever flavor is currently in it. Give it a quick dry burn or two and blow one more time for good measure. Now it should be set for a fresh new flavor.
Put the atty back on your battery. Drip 3 or 4 drops down on the bridge of your atty (wire mesh looking stuff where the cart filler usually touches).
If you have a drip tip, use that...otherwise, Put an EMPTY cart with NO FILLER back on the atty.
Vape

It should last for several good puffs. 8-10 at least with full vapor...and far more before it starts to 'taste like dry coil'. Many people report that 3 to 5 drops on a regular 510 atty is pretty much equivalent in puff numbers to lighting up a tobacco ciggy.
If you liked that.
Get a drip tip...
All you have to do is add a drop when the vapor starts to drop off or it tastes a little dry. You'll find your sweet spot, but for constant vapers...I'd guess average is to add a single drop right into your drip tip every 5 to 8 puffs if you want to keep the atty wet constantly.
You'll drip more often than with the carts....but it may really bring out the flavors for you, and you'll spend less time tinkering with the carts. Just drip drip every now and then
Cartomizers
Don't over-fill them. The trick with these it to have just enough juice in them that the filler is kind of slushy all the way through...from top to bottom. There should be no 'pooling' of the liquid that you can see.
Blow through a freshly filled carto into a tissue a time or two. Don't be shy....use a pretty forceful blow, as you want to push out any excess juice from that center tube. Wipe the entire cart really well before using.
A drip tip instead of the stock end plugs can also provide a much more comfortable vape with far fewer juice in mouth adventures. They also make it easy to keep a carto topped off.