If something doesn't require a meaningful decision--that is, one where there are significant pros and cons each way--I don't feel it's worth my time or my players' time to keep track of it. 90% of the time, rations don't meet the "meaningful decision" bar: If the party has the carrying capacity (mostly they do), and if they have the money to afford rations (mostly they have that, too), then packing enough rations for the trip is a no-brainer, so why not just assume they do it and don't worry about it?
The other 10% of the time, where the party is short on carrying capacity, loses their pack mule, et cetera, I'd probably call for tracking rations.
I do feel like this is a longstanding weak point of D&D, going back across all the editions. It would be nice to have wilderness survival rules that acknowledged this distinction: Most of the time, you don't have to worry about rations, but when rations suddenly become a concern, there should be a way to "engage" the survival rules without having to go back and figure out just how many days' worth the PCs would have purchased in town.
(Of course, with spells like goodberry around, it hardly matters. I may be banning goodberry. We'll see.)