The higher your Sneak skill, the easier it is to remain undetected, steal and item, or pick someone’s pocket. Successfully attack while undetected grants an automatic critical hit.

Sneak is a nice skill that allows you to steal loot, score sneak attack criticals, and move past enemies when you’d rather avoid (or at least delay) a fight. Most items can be stolen by being patient and waiting for potential witnesses to leave, and sneak attack criticals are more easy to score than ever, now that you have iron sights and don’t need to approach as close. Both of these factors mean you really don’t need a Sneak score that’s terribly high, although if you want to sneak anywhere near an enemy, much less past one, you’re going to want the Silent Running perk… which requires an obligatory minimum investment of 50 Sneak. You can wait a while before investing in Sneak, since you don’t need to sneak much (in combat at least, where a high skill matters) until you have the Gobi Campaign Scout Rifle.