diff --git a/TODO.md b/TODO.md
index 5cd6fd1..59425af 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,3 +1,7 @@
 - create classes for read/write, read-only (volatile), and write-only memory locations
   - zero page and absolute
   - but how do we encode it? subclassing?
+- writing a value does two things
+  1. establishes a fungible "init" phase (where we can take advantage of accumulator sharing)
+  2. allows read-leases for some known scope
+- but what then is a write lease and how is it finite?