

It is really only there because the amount of "clean air" a filter you pick up can provide differs from one filter to the next. The time that comes up when you pick up a filter is simply a consolidated reservoir of time that you have collected. There is no downside to doing so, considering how out of hand the cracks can get. The fact that it only lets you interact with a mask that is in better shape than your own makes it easy for you to make the decision to pick it up. you are aiming at a discarded mask on a shelf) is in better shape than the one you are wearing meaning it has taken less damage than your current mask. Gas mask replacements only come up when the gas mask you are looking at (e.g. The answer is a combination of Draedalus' answer and Kotekzot's comment.
