I'm a great believer in using the right tool for the job, so I use a variety of products, e.g. WD40, penetrating oils (Kroil is my favorite), Kwikee KwikLube lubricant, Boeshield T9 corrosion blocker, and white lithium grease. If I could have only one, it would probably be the KwikLube, but WD40 would be close as a general purpose lube & loosener. I use those two often around the house and car.
is a spray that lubricates well, clings for months even outdoors, provides some corrosion blocking, and doesn't have a residual aroma (that I can smell anyway).