Crab writes:
"perhaps GA owners might like to detail what performance calculations they complete before getting airborne and then how much attention they pay to performance limits once in the air"
Not an owner, but a low time renter/commercial student operating Robinson equipment exclusively. My pre-planning is primarily of the "scenario based" methodology. That is to say, I've got a number of pre-planned, pre-calculated scenarios that I go by. If I'm planning a flight that does not fit neatly within one of those scenarios, then it's time to spend a minute or two with the spreadsheet, which is not a big chore since it's literally that fast to do a W&B with the spreadsheet. In my neck of the woods density altitude is rarely a planning factor, with most operations below 1000 ft MSL, and it doesn't normally get terribly hot in New England. However if I thought I was going to be operating in, say, the Presidential Range of New Hampshire, particularly in the summer, I'd certainly by sharpening the old pencil!
As for performance limits in the air, certainly one does not exceed MP limits, allow rotor RPM to decay, allow carb temp. to be low, descend too quickly below 30KN, or exceed maximum speeds, to hit the high points. Also scrupulously avoided are downwind approaches and high speeds in turbulence.
However, with a vast amount of highly forested and/or crowded urban terrain, operation in the avoid--er--"money"
part of the HV chart is not unusual with respect to certain steep approaches or max. performance take-offs to/from confined areas, with all due regard to minimizing time in those parts of the chart, of course. Some of those operations have required quite scrupulous pre-planning on my part. So far I've only been surprised once by a low-RPM warning on a max. performance take-off, but that was more of an issue of technique (still learning, I am) than poor planning, and was easily solved by moderating the climb rate a bit.
Power checks are also in the repertoire, but most of the time I am operating fairly light, so it always gets my attention when that first hover power check says I'm not light!
Anyhow, I suspect your demographic is a bit skewed here, Crab. Anyone that reads pprune for fun and profit is probably paying a bit more attention to their flying than the average Joe.