I tend to vape multiple flavors throughout the day.x So ... right now, I have 4 PV's at my side.x I have a White Penstyle with Coffee and a Maroon one with Pear Lung, then I have my e-Cigar with a Tobacco/Cherry blend and a 510 with a dedicated Clove atty.The Cigar pretty much stays with the same juice flavors all the time.x I may go with a straight Tobacco or a straight Cherry flavor sometimes.x But basically those 2 flavors or combination there of at all times.
The 510 ... well, right now, I pretty much am using it for Clove only.x If I want another flavor on the 510, I'd use a new atty.
So really, it's only on my Pens that I change flavors. If I want to change flavors with those, I typically vape it dry. Then I vape a few drops of straight VG dripped on the atty to clear ou tht eold flavor. Then, I add a cart with a new flavor.