I hear about “sentimental” versus real value. Explain?
Don’t confuse the two. Say you obtain an autograph in person. You had a personal connection with the celebrity who signed the autograph. That makes it a special memento for you. This does not, however, contribute to its real value based upon the four factors above. It often is hard for the collector to step back and look at their treasures objectively. We do it every day. There are a few exceptions. If the celebrity who signed in-person is especially desirable and in demand – such as a standing US president – then your provenance of obtaining it in person can add appreciably to the value.