Replacing Gutter Fascia?
Assuming the aluminum fascia covering is sound (i.e. not bent all to hell or oxidized/corroded) and the wood underneath is in good shape, replacement criteria would be strictly aesthetics.
Yours looks bent up a bit and stained in places, but if it were mine I would attempt to (carefully) beat it back flat, caulk the holes, then hit it with a fresh coat of paint.