Just do not know what it is about Swiss passes but they baffle me. The info I've found never seems to answer my basic questions. (End of rant. It's probably me, not them.) Current issue is with Swiss Saver Day Pass--simple question does it permit you to just jump on any available train without reservation all day, on any selected prepaid day? Or do you need to make advance reservations? Title sounds like that should be the case, but info on line doesn't provide a definite answer. Thanks for any guidance.

" simple question does it permit you to just jump on any available train without reservation all day, on any selected prepaid day? "

Yes, it does. The only domestic trains in Switzerland which have to be booked ahead are Glacier Express and Bernina Express. But there are tons of other trains along these itineraries where nothing has to be booked.

Thanks so much. Just what I was hoping to hear. Solves most of my issues. Hurrah.