Sqeaky doors?
 

Just use WD-40 or what should I use to fix doors that squeak?

Start with wd-40. If that doesn't do it you can get new hinges pretty cheap.

WD-40 is actually the wrong choice. people spray wd-40 on their bikes, cars, doors, whatever and they don't realize that it washes away the longer lasting grease that is supposed to provide lubrication. i would take off one pin at a time and rub some white lithium grease on easy pin. it will last for at least a year.

dt

any others?

WD-40 works, however it is definitely not your best choice. First verify that the squeaking is indeed coming from the hinges, and not from the door rubbing the casing (this is unlikely but worth a check). If it is indeed the hinges, pull one pin and use a small amount of grease just like dtheriault said. Then replace that pin and do the next one. While you have the pin out, look at it, make sure that it is not overly worn, if it is worn, just replace the hinges.

use some 3 in 1 oil, or something similar. If you have chain lube for a bicycle, or something similar, that should work also.

i've also just wiped off the hinges...sometimes it's the dirt that's caught in there that is the cause of the squeek.

and if you're really cheap, white petroleum jelly will do the trick for a while as well.

white lithium grease

use the white lithium grease like everyone suggested. if you must end up using wd40, be careful to watch the dripping...it will be quite nasty and will leave dirty/black streaks on the hinges/door if not cleaned up.