Agreed, these things should be on a gear list; they're on mine.
I'm in the ziplock-as-mapcase camp. Easier, cheaper, re-useable (for a while).
My gear list has a sort of generic trip weight for mapsheets plus s gallon ziplock to carry them in. One could guesstimate map weight based on days of trip, but apart from being a picky PITA, the type and number of sheets I carry per day (or per N-miles) can vary a lot with the trip.
In the "wallet" category there's a ziplock, sometimes even a simblissity wallet (nice to have something that looks like a wallet when you go into towns), drivers license, a paper copy of my health insurance card, credit card, and paper money --- about the same weight of this stuff on every trip so I consider it an invariant.
Prescription meds and any other pills (multi-vitamin, Omega 3, whatever) is also something one could do on a per-day basis but I ... don't, just assume something like a week's worth for any trip.
I hesitate to even mention t.p. here, but for those that carry it (and also separately for those that pack it out), there's arguably per-day variant weights there.
How detail-oriented you get on this stuff might depend somewhat on your overall base weight. For those in the traditional camp, this stuff is in the noise level. I'm in the lower half of "light", but almost never "ultralight", so it's somewhat significant but there's still a point of being too picky. For those at the more extreme light end of the spectrum it's a little more meaningful to talk about the weight of a couple more piece of paper or a second ziplock to carry the maps not carried in your pocket or whatever!