It's not the length of time. I've been at it six and a half years and I still love good juice. I do find vaping higher quality juice has left me less tolerant of the lower quality stuff. It's kind of like if you only eat in 5* restaurants and then you try street vendor food. After DeejStuff (5*) closed, I bought some juice from the vendor I used before that. It's not terrible, 3* and some 4*, but it's definitely harsher and less refined than what I'm now used to. I can vape it in small quantities but none of it is an all-day or even an all-hour vape. (On the other hand, my Ahlusion Boba Tea, Chocolate Cream and Peppermint Mocha are on on a back shelf. So far they've been steeping for 7-10 months. If they're still ghastly after a year, they're going down the drain. Other than them, all the Ahlusion I've gotten has been 5*. I don't always like what I order but the flavor is what it should be.)
If you want to clear your palate, maybe you can vape unflavored for a week.
