Right now I have a Ti 83 that I have had since eighth grade. At this point (wrapping up my first semester of Calculus) I use it infrequently -- mostly to find decimal values and to double check my arithmetic before I submit work.
My university "recommends, but does not require, a calculator capable of advanced functions (such as a Ti 89) for use as a learning tool to aid students in familiarizing themselves with the material and concepts presented. However, no student will be allowed access to a calculator of any kind during any test or assignment which contributes to the student's final grade."
Thus far I have put off upgrading in part because of the expense, and in part because I was worried about becoming dependent on the calculator's capabilities. However, at this point I am starting to wonder if not having one is going to put me at a disadvantage as the material becomes harder. What is your opinion -- is a Ti 89 a valuable learning tool or an expensive crutch?