diff --git a/future-plans.md b/future-plans.md
index 98a76ac..0926a7e 100644
--- a/future-plans.md
+++ b/future-plans.md
@@ -206,6 +206,13 @@ Some fields naturally belong together (e.g. `frequency_stability` and
 Structured records are the more powerful option but require a schema system and
 more complex UI. Grouping/linkage is a lighter short-term win.
 
+As fields are shared across entity types (components, bins, bin types, and anything
+else added later), the field pool grows to span unrelated domains. Groups also serve
+as a domain filter in the field selector — when adding a field to a bin type, you
+should be able to filter to e.g. "physical" or "storage" fields rather than seeing
+electrical component fields mixed in. Each field should be able to belong to one or
+more groups.
+
 #### Semantically-aware formatting (acronyms, proper names)
 Formatters that apply title case or similar text transformations can corrupt acronyms
 (e.g. `NPN` → `Npn`) or brand/proper names. The root cause is that free-text field
@@ -416,6 +423,23 @@ dimensions are pre-filled — no need to re-enter for every bin of the same mode
 This also enables filtering/grouping bins by type, and makes it easy to re-process
 all bins of a type if the corner algorithm improves.
 
+### Generic fields on bins and bin types
+Bins and bin types should support the same generic field system as components —
+arbitrary key/value pairs from the shared field definitions. Examples: color, material,
+manufacturer, max load, purchase link. Bin types carry the "template" fields (e.g.
+nominal dimensions from the datasheet) while individual bins carry instance-specific
+fields (e.g. actual color of that specific unit).
+
+Because fields are shared across components, bins, and anything else that grows into
+the system, they will quickly span unrelated domains. Field grouping (see Field system
+section) becomes important here so the field selector can be filtered to show only
+relevant fields for the current entity type.
+
+### Duplicate bin type
+Bin types should be duplicatable — common when you have the same physical container
+in different colors, sizes, or configurations. Duplicating copies all fields and
+dimensions; the user then adjusts what differs.
+
 ## Grids
 
 ### Grid view layers