I think I have just about everything I need in my BOB. Sort of...

I don't have a water filter. I always figured I would just boil my water. And I still do intend to boil my water, whenever possible. But I was thinking about some situations in which I might not be able to wait for water to boil, and then wait for it to cool down. So I decided I'm going to get a water filter, just in case.

Katadyn Pocket Microfilter = $200
Katadyn Hiker Microfilter = $60

Is the extra $140 necessary?