Should I be greasing my U joints?

Precision, Spicer are what I use.
Typical napa stuff.
Usually 1 maybe 2 greasings are all they get and go 200k+.
I'd use an air gun to dust off grease boogers or just run a rag over it.
Its always a good idea to take a spin up the driveway or block n back then clear/wipe any grease off. Gives it a chance to push out any unnecessary amount.