User+Stories+I.N.V.E.S.T

=I= Independent
 * Avoid dependencies between stories

=N= Negotiable
 * Not contracts, but place holders for conversations

=V= Valuable
 * Can be directly tied to something a user or customer (purchaser) wants

=E= Estimable
 * Can fit into an iteration and be approximately estimated

=S= Small
 * Can be done in a "short" time & its details fit in a conversation

=T= Testable
 * Can describe ways in which we know the story works