CloudCuckooMan, variety can be the spice of (vaping) life.
Most analog smokers settle upon one particular brand in one particular strenght (for instance, Marlboro Ultralight 100's) and smoke those exclusively.
The fun of vaping is playing with all the different flavors.
And, like you, I get the dreaded "dead-bud" syndrome.
My solution has been to rotate. Every Saturday morning, I charge up five fresh (brand-new or cleaned) Echo-e cartos with five different flavors, selected from my stash somewhat at random. I'll include a "tobacco" or two, a menthol or menthol blend, a fruit (cherry, lemon, lime, whatever) or two and sometimes an oddball (whisky, Key lime freeze, whatever). During the week, I'll top off those five cartos as needed. Then, on the next Saturday, the five cartos go in the wash bucket and I'll select another five flavors, all different from the previous five. All told, I probably have 25 or so different flavors I like enough to vape, off and on, for a week. Very often, I won't get back to a particular flavor until a month has gone by -- then it's like rediscovering an old friend.
Just what works for me . . . your mileage may vary.