In my view, if you only fly daylight VFR, you don't need backup ASI or altimiter.
I agree 100%.
Unfortunately both authorities with whom I'm involved (UK and Oz) think otherwise and insist we have these things. The UK even makes a standby compass a mandatory item.....chocolate fire guard springs to mind
Paul,
I don't think we need to have backup ASI or altimiter in OZ (?). At least nobody told me!
cheers
r