you will always find basic ressources at home you may multiply (and sometimes even more!)
for the rest you got the custom craft.
well sure. that's what I said. But before this latest update you could go scavenge, come back and put it in a scavenge pile, I usually left the metal cabinet in the basement full of stuff. It had 2 of every item I ever found. You could always just go open it again and replicate to hearts content of any item in the game that you had found or crafted. Now you can no longer put anything into the cabinets/piles. So it's much more limited than before.
Obviously you can do the same thing with the custom craft and instant crafting but it's a lot more involved especially to produce enough to never worry about it again. Bullets for instance I always did 4096 of them.