I recently dropped Slicing in favor of Scavenging so as to be a little more self-sufficient with my Cybertech crafting sideline. (One too many visits to the GTN to find that the mats I need aren't available.
I've just started Hoth, but have suspended active questing to grind Scavenging to a level where I can pick up the resource nodes; I'm funding the companion scavenging quests with gray-level space missions.
What level of scavenging should I reach to be able to harvest nodes on Hoth? More generally, has anyone worked out "Minimum Gathering Skill Levels" for the various planets?