Replace the minimum amount for the strongest repair. I bought 2 skegs from BAM and cut out the sections I needed to restore mine back to original shape. Mine had the normal do it yourself file the edge smooth when I bought the boat. 2 yrs later and still perfect.
You can see the leading edge that I replaced on one, and the lower 1/2 on the second, only because I tried to take a little bend out of the 2nd only to have the corner break off. I thought it was best to replace with 1 section vs 2 sections. You don't have to gut and strip as I did, I just go all out whenever I do stuff. I can not find the repair now even though I did it.