Brake pad life is totally dependent on your driving style. Lots of highway km, or lots of engine braking, and the pads may last quite a while. Just something to make serious note of every time the wheels are off (Swapping between summers/winters).
Spark plugs can be done by anyone, just make sure they gap em.
I'm cheap, and the valve covers are a pain in he bum, so I just let mine weep. I kinda like the burning oil smell, fond memories of the Honda I had in high-school.