Our hangar located at the definition of Hot an High, today's conditions Elev. 7,340 FT, 32°C, 30.10, you figure out Density Altitude and it should come out to something above 10K,
Anyway there is a flight we do everyday at around 13:30, 50 Gal. 1 Pax, and lots of equipment, at this WT the helicopter will barely hover IGE (about 10 inches off the ground) always biting the TOT redline, if you get a little wind from the wrong place you will have to let it sink to the ground (even during taxi) to avoid going over the redline, that's the way the JR flies Hot and High, (I should say barely flies) Sometimes you have to hover to the taxiway to lineup with the wind, then start your TO run, this sometimes takes more 5 minutes to to do this so what I do is taxi in the TO range, then settle down let it "breathe a little" a couple of seconds and then begin my takeoff again of course in the yellow arc again.
Our engines spend an incredible amount of time in the yellow arc, but never more than 5 minutes at a time, we have two JR's with engines that have more than 9000 hours on them, we have never had a problem with engines not making their TBO's or not passing their power checks, as long you use common sense and don't exceed limitations published in the books these aircraft will take care of you.
Its the only way they fly around here, I might need "attitude readjustment session", but like an old timer from a major US operator told me the other day, "we don't baby our aircraft around here, we just stick to what the manual says you can or can't do and get the max out of the aircraft"