Open when... you know who I am pretty well. When I am sarcastic, when I am serious, when I'm angry, when I'm happy, when I'm insecure, when I'm overjoyed. It's hard to understand someone else's writing as they do without really knowing who they are personally.
"Open when..." envelopes! These are perfect for military deployments or long distance relationships, etc. I grabbed 10 envelopes and put hand written letters in each of them, some with little treats. I also made an 11th envelope for just pictures!