This is more of a thought than an actual idea. Not sure what the intention of the devs is when it comes to this matter. Is it planned that we'll one day have to migrate to another server, due to resources depleting, or is one server supposed to stay inhabited "forever"?
If it is meant to stay inhabited forever, I think we'll sooner or later be facing problems with depletion of resources (or already are). Especially when Salem goes into open beta or is released, where we (might) see an influx of players, this just might mean that the resources will deplete that much faster.
Sure, depleting resources is realistic, and finding a big lime field for example is a part of the game to save yourself trips to other lime fields. But when that lime field depletes and I'm sure many have experienced this already, in come the alt spam just for gathering lime or granite and transporting via Boston - which is tedious, unintuitive and a bad game mechanic, if you ask me.
So I would suggest adding mechanics that slowly restore lime quarries and either respawn granite boulders, or restore granite pits/quarries/mines, if such were added one day (please add them, many suggestions already on this).
Slowly restoring lime quarries would mean that you'll still have to look for a bigger lime quarry if you wanted to mass dig lime, so it wouldn't really remove this aspect of the game.