Originally Posted by JustKay
The game seems to adjust rarity based on whether you have an outstanding goal for an item and if you have a low amount of that item. Due to a haitus, I only started on this goal in the last month or two. I have been keeping a ratio of 90:35:25 for the plants and this has allowed me to hack away at the goal at a reasonable rate (at 7 or 8 inscriptions). The key think I notice is that 20 seems to be a tipping point. Having less than 20 of anything results in a reduced drop rate (having zero make is extra hard). This makes sense since when a new goal comes out, and new items are introduced, people can't rush to complete it. Everyone has to start from that zero state. They have to slowly accumulate up to 20 items before then drop rate evens out.
So for all my items in my inventory I keep a floating supply above 20 (except stones and timber since those don't seem to be affected). So if you're the impatient type, and always use items as you get them, then you will revisit the 0 state many many times. It's tough resisting the urge, but once I'm up to 20 items it's a smoother process of accumulating items.