Appreciation - how to factor it in?

[Riley F.]

For buy and hold investors out there, how do you guys think about appreciation and how do you factor it in to your buying and selling decisions, if at all? What key factors do you use to measure the potential for appreciation and where do you find this data?

As an illustrative example, would you be willing to go down in CoC yield from 15% to 10% for the potential for appreciation, all other things being equal (I know that they never are).