My knife evolution is as follows.
I started hiking with a Frost Sheath knife w/ a 4 in. blade. But no place to put it on the beltand heavy as I began to adopt the light weight approach. I tried a neck sheath, but it was always hanging in the way of my line of sight.
Next, I made a hacksaw knife. It was everything I needed, but it had to be stored in the pack and wasn't availablefor odd jobs while hiking.
Finally got a three inch pocket knife. It's always ready in my pocket. I've been carrying it for the last three years.
That said, a simple swiss army knife might pay for itself. I hiked for 5 weeks this year and it was real interesting trimming my toenails with the pocket knife after they got vampire long.