Yep. I carry my knives clipped to the rear right pocket and only notice them when I grab my wallet which shares the same pocket. The front right is occupied by a Ruger LCP + spare mag in a pocket holster (which also disappears). One of the worst feelings I've ever had was to reach for my knife or pistol and realize I didn't swap them over to the new pants when I changed clothes.
As far as losing knives, I've never lost one for more than a few weeks, but it was a Kershaw Leek that was not clipped to my pocket at the time. In jeans, I can carry either clipped or unclipped with adequate retention. In the scrubs I wear at work, I really need to carry either front right pocket clipped or in the waistband clipped. Scrubs have horrible pocket retention on anyting.