I have never done fent so take my advice with a grain of salt. I am on the tail end of my 100th hydrocodone withdrawal( I know can't really compare with fent). First good on you for the clean time. In my experience even after 6 months if I use 1 day I feel like shit for 3 or 4 days, not full blown withdrawal but enough that it sucks. If you do decide to use just be careful because I'm sure if nothing else your tolerance has probably dropped from your normal dose.