Is there any other adjustment or lubrication that needs to be routinely done on the hinges?
I replaced mine with a set of these not long after buying the car (which was less than 6 months ago):
For Nissan Elgrand E51 Heavy Duty Tail Gate Boot Struts 2002-2010. These are upgraded heavy duty struts that give an extra 20cm/8 inch lift to the tailgate. They are a direct fit with no modifications required. PART NUMBER: E51TGS.
www.ebay.co.uk
They claim to be a) heavy duty and b) 8 inches extra lift, but as far as I can tell, they aren't either - I still need to manually push the tailgate up to get it to move the last 8 inches or so of opening, and even then, I would estimate the clearance between the ground and the bottom of the tailgate door is no more than 5 foot 9 or so (which isn't great when I'm 6 foot 2).
My car has new heavy duty rear shocks and springs so it's not a saggy rear end affecting the tailgate height - just seems not to want to open as far as it ideally (or theoretically) should.
Should I just bin these struts and get the ones from JDM? Or are there any other points I should be looking at first?