WD40 sucks. Let all the aromatics dry out of it and see what is left, the residue is best described as exactly like bubblegum which has dried enough to be tacky to stick to everything. That residue almost impossible to remove too, solvent won't touch it. I pretty much don't use it on anything anymore.
Oil works but dries out and runs off too fast, you'd have to oil the hinges every month.
Spray on like lithium grease best, and what I use. Ford used some sort of specced grease there. The grease stays for a while.
While new hinges are a great idea, if the hinge bushing is worn but still fairly thick-walled and not breaking up in pieces you actually can re-adjust the door to work and latch perfectly and with little effort. I've done it to cars before. The door does not really care about the hinges as much as the car owner, it merely hangs against whatever surface is there. The looseness does not really matter since door weight holds door pretty much one way only, the only sign you'd ever have is hitting a bump hard enough to lift door from inertia, do that and you'll hear far more than the door clanking against the looseness. As in the whole car will make noise there.
I carefully locate a jack under door using wood to not bend bottom edge and then forward/rearward until find the balance point, lift door slightly to negate its' weight and then loosen hinges and retighten after moving. A few times and you can get that door closing as well as a brand new one. The door weight will then hold door to that new location.
I've had ones that wouldn't close without slamming as hard as you can, when done you could close and latch with a very slight push, like a new one. One finger opening and no door hanging on the latch post anymore either. And no hinge changed at all. It's all based on getting back of door up higher to re-align w/latch and getting the door weight to settle onto hinge good and solid right then too. I figure if hinges actually truly dead you will hear the door creak or rattle as the car moves over bumps, it hasn't happened to me yet.
Now if the hinge bushings are broken or missing, yeah, you need something there to take up space, it just doesn't have to be like 'within .005" close', you can get away with up to .030" wear there.
Did my '80 wagon like that and previously my '74 Mustang II, the doors operated fine after that for years more and nothing partwise changed at all.