Generally speaking

yes.

Seriously – it depends.

neither 🙂 ive got talas had them on ht now stuck them on the sus to try but i just dont feel the need to adjust them at all. Maybe depends on the frame

Nope – Just stick everything in the middle and ride.

Neither/both.

Its nothing to do with the back end. Everyting to do with bar height at the front. For me, any bike with longer than ~ 120mm forks needs TA to be ridden up proper steep hills. Otherwise the relationship between bars and saddle is all to cock and I can't get enough weight on the front wheel.

Fixed travel forks on my xc bike and SS. adjustable ones on my BFe and Turner.

Even more seriously – neither, I'd only use one for a long travel bike – 150mm odd.

Personally I can't be arsed to get off my bike and start twiddling knobs whenever the gradient changes, YMMV.

I seem to have gone u-turn coils on all my bikes now. (as I don't like air)
I build my bikes up from s/h frames, it's easier to get a good match.

Even more seriously – neither, I'd only use one for a long travel bike – 150mm odd.

+1

When I and some mates first got u turn revs that did 130 to 100mm, we spent ages winding them up and down for everything – for the first 3 rides, thereafter they got left at 130mm. If I had 160+mm forks maybe I'd use it, but even my 140mm Pikes are fine if you get a bit of weight on the front, its just a case of adapting technique.

Depends on bike geometry. I twiddle them down from 130->100 on my TranceX on longer climbs – makes the front easier to handle so is less tiring

For me, any bike with longer than ~ 120mm forks needs TA to be ridden up proper steep hills.

seriously??

i think there is a use for it, for example when i had 150mm forks on my SS i'd lock them down for long climbs because you lose a lot of energy to the compression of the forks which just makes things harder. but on my 150mm FS i don't have lock out on either f or r, i just don't think that you need it if you have proper technique/weighting and see far too many people depending on lockout.