right now grinnich completely refreshes stock once every 24 hours. this means there is no point in checking grinnich more than once per day which is odd. i personally like it a lot when i get to interact with NPCs often.
i think it should be changed so they restock 1/6th of their inventory every 4 hours, which maintains the same 1:24 ratio for restocking. of course im spitballing the exact numbers but you get the point.
I would make the change in this way: Since sleeping doesn’t really have any impact in the game (the bonus is laughable) we could rework this two aspects of the game. This is my view and opinion of how could it be changed.
First I would make that sleeping will fully heal you (no focus gain or loss) and 1 day (ingame) would pass. With this “time” difference I would make all vendors refresh stock thus solving the issue with the sleeping mechaninc and vendors being almost forgettable once checked for all the day left.
In case of the special vendor on saturdays I woul’d make really big changes other than (if possible and if makes sense blance wise) the items sold where (if there are like 12 items) 1/3 or so, focused around your main stat/s so there is more incentive to buy items/make a better build not as reliant on luck/randomness.