For anyone who ever has guessed the exact number of jellybeans in a jar, correctly picked a 40-to-one long shot to win a horse race or accurately predicted what Donald Trump would say next, Antiques Roadshow's summer reruns should be a natural viewing choice.

For the past few summer seasons, the highly rated PBS series (8 p.m.  E.T. Mondays, check local listings) has replayed some of its earliest "vintage" episodes in which the only change is that after an appraiser's monetary value for that year has been shown, an updated appraisal is added, side-by-side, on the screen. The new numbers can be surprising when the value has dramatically increased or been lowered over the intervening years. In some rare cases, values have jumped by $100,000 or more. 

In the July 20 show, for example, there are two objects — one is a Norwegian fiddle (left) — that have more than doubled in value since they appeared 15 years ago during a Roadshow visit to Madison, Wis. 

Two questions come to mind while watching these updates: What are the reasons for the changes and who does them? Because no easily found explanation seems to exist on the program's website, we made a call. The following explanation from the Roadshow staff pretty much explains the process:

"For the updated values in the vintage hours, Antiques Roadshow consults with their 150-plus featured appraisers. Most of the updated valuations are directly from the original appraiser, many of who still tour with the production. When revisiting an item, the appraisers consider changes in the antique market, subject-specific historical and/or current events, recent auction records and more. If the original appraiser is no longer working with the show or has since passed away, Roadshow will consult with another appraiser in the specific specialty."

This is a new twist on the ages-old rerun season, one that helps make something old less worn. It's natural to guess if and how the values change, but hard to do so correctly. Opinion: Predicting Trump dicta probably is easier but surely not as much fun.