The line between preparedness and redundancy is fluid in concept, and constantly differs in practice based on experience, skill, budget, personality, and intent. So no one answer fits all.

I agree with those who suggest looking not to particular gear so much, but to survival function. I start with whatever gear and supplies I think is needed to conquer the "Rule of Threes:" you can perish in 3 minutes without air, in 3 hours of exposure to harsh environment, in 3 days without water, and in 3 weeks without food.

In putting gear and supplies together I think in terms of layes and of multi-task flexibility. I do not consider them redundant but complimentary.

I carry one layer of stuff that seek to address each of the rule of three challenges in my EDC, in my PSK, and in my normal use camping / hiking / traveling gear. If I am traveling in my vehicle I have a fourth set in my vehicle kit. In this way I already have multiple sets of gear / supplies.

Where I can, I choose gear and supplies for each layer that are also multi-function. Things like knives, paracord, freezer bags, space blankets, candles, fishing monofilament, fish hooks, snare wire, duct tape, etcetera, each have so many uses that carrying each creates further levels of preparedness. Learning and practicing multiple uses of gear and supplies is a major preparedness theme.

Edit: I also choose to learn "primitive' skills that offer the ability to recreate whatever I need from the environment with no gear or supplies.