BP, the real answer is that they can be far more cost effective than most others. As said, heaps of items retire at 2200 when you do O'haul of gearbox, big and small and all the rest. An aircraft at 2200 hours will be worth say 50K.
At 4400 hours there are a couple more throw away items like the head and tail boom so at 4400 the thing will then be worth only 40K say.
After the fourth life (8800) it always pays to re loom it, at about 4 or 5K as electrical snags in the field, or even on a airport with a sparky not far away, will soon cost more than that.
The biggest bug bear is the engine which is TBO'd at 2000, unless it is private where you can run through on condition to 2200.
Belts should last about 800 real hours, there are more extensive service lists at 300 hour intervals and the 12 year limit is statutory on the retirement components and O'Haul the rest if you haven't been smart enough to run it out of hours by then.
But the 12 yearly or 2200 hourly airframe inspection is just the same as the major on most others, more a paper war than anything else.
There are some silly staggard times on the frames and T/R blades.
Any Robinson Approved licensed service centre does the lot.
In real anwer to yourself and TC the real trick is you can use the proverbial back of the envelope better with these than most others, here's how.
Divide your 2200 hours by fours years, take your finance over four years, over here you get a 25% tax depreciation every year, get the drift?
You might like to take a 50K balloon, it's up to you and your pencil.
At four years you will arrive at the tanatalising dimishing point of all aircraft where they are worth almost nothing with your component times having nicely marched down in time/value with finance/capital and tax depreciation.
It is also convenient because you only have to insure that which is financed, and if that matches your real value then you are not wasting isurance dollars, neither will yuou be over or under insured.
It might even pay you to run a fourth machine if you are working three already @ three years each / 2200hrs.
But then again if you bought it to look at, you shouldn't be asking.