Are your Defender door hinges stiff or hard to open?
Use a squirt of silicone spray to free the door hinge, you may find rust coloured oil dripping out that’s fine and can be wiped off afterwards.
Now the hinge is working as they should use a squirt of white lithium grease spray on all the hinges once every 3 months, I do mine to keep all the hinges working as they should.
There is of cause on other option….
If your hinges are too worn, the doors may drop and make it difficult to open or close the doors at all. JGS4x4 offer a set of Heavy Duty door hinges with all fixings, these are stronger than the originals and should last much longer.