I still have, and use very regularly, my calculator purchased in 1982. In fact, its out on my desk right now, cover off and in prime position for use. Since its purchase in 1982, its only on its third set of batteries (uses 3x 357/303 button batteries) and I still have the original user manual on my office bookshelf. I reach for this calculator rather than use my phone calculator apps or a PC calculator. I just find it quicker and easier to use. Oh, and I have been a fan of RPN since about 5 mins after purchasing the thing so many years ago.