90 % of the time (that is 90 % of the time I am awake...) right front pocket. Biggest size I am comfortable to carry there: Endura 4. Anything longer (or even a bit shorter when having a deep carry clip) reaches to deep in the pocket which is not ideal when riding a bicycle or doing higher steps when mountain hiking (could even push the knife out of the pocket).
Since I normally have nothing else in the rfp, widefolders (Manix 2 LW...) don´t bother me, just if they get to long. As a matter of fact I found: Wide, but not too long folders with a large footprint that are on the other hand very light (again Manix 2 LW) are the most comfortable and stable to carry.
Back pocket does not work for me with the larger sized knives I tend to carry: I have an old back injury, and when sitting for a longer period of time with a larger folder in the back pocket I sit a bit less "natural" and my back does not get better by that...
IWB just if I have to, for example in running shorts that have no or just very thin and floppy pockets, and I want to have the knife really secure.
In my day to day life IWB just does not work for me: Awkward to access and put back the knife when wearing several layers untucked and maybe a hip bag
As soon as I am wearing a pack that has some secure kind of front (and by that quick to access) pocket, I tend to put my folder there when mountaineering and hiking, since I once lost an Endura out of my front pocket in the mountains
In mountain pants that feature a zippered front pocket the knife gets thrown in there, mostly it is the Chaparral then.
Top three going by pocket-time: Endura 4 in VG 10/Micarta-scales; Stretch 1 in VG 10; Endura 4 in HAP 40