For myself, I usually need 3-4 weeks to get my diet @ 95% of where it needs to be, so doing a 6 weeker almost seems pointless. But I use oils exclusively now and money isn't a concern at the moment so I can rotate multiple compounds and I don't spare myself the fancy stuff either - I gleefully implement GH, MK, Primo, Mast, MENT, etc and Aromasin, insulin as needed, T4/T3. Granted, I don't take large doses of anything but rather take the approach of having a complete cycle because it works better and allows for much greater gains in the long run.
When you have options and a neverending budget for this stuff, longer cycles are the way to go and opting for more complete anabolic cycles that include 3 to 4 different pathways to enhance muscle growth.
Mind you, I'm never gonna suggest to do stuff like this without the right ancillaries and supplements to keep BP, platelets, cholesterol & organs in tip top shape.
It goes back to my epiphany this last summer that people on skimpy budgets ought to either 1) adjust their dose and cycle length to allow for proper ancillaries and PCT (including blood work) or 2) don't do the steroids and rather opt for spending the money you do have on something like Somatozine (or some other MK supp) and extra lean meats & some organic food options that people generally opt out for b/c of price.
And before anyone wonders, no, I'm not a rep for MA Supps although I probably should be since I love his products so much, lol.