[pct-l] Need extra shoes?

[pumpkin1 at thegrid.net (Nancy Sexton)]

I will be doing about a 400 mile section hike from Lake Tahoe area down to Mt. Whitney. I am training in the shoes I will be wearing (Merrill low tops), so will maybe have 300 miles on them when I leave. Will I need to resupply myself with a new pair of shoes before the end of my hike? 
On a similar note, do most people bring an extra pair of shoes, sandals, river shoes, or whatever? I really don't want the extra weight, but think it might be helpful to have an extra pair.
Nancy