Swiss train tkts, so many options, please help.

Those are the Half Fare Card prices, so you would need to buy the Half Fare Card for 120 CHF to benefit.

The default setting on the Swiss rail website is with a Half Fare Card. Without one, you need to “uncheck” that, where is says “Price Display” on the first page, or when entering travelers on the purchase page.

There is no advantage to buying point-to-point tickets in advance on Swiss trains, unless you see a SuperSaver Ticket. Those are limited, and they do sell out and become unavailable later. They are also totally inflexible—if you miss the train for which you purchased a SuperSaver ticket, it is gone and you must pay for a new one. The prices are tempting, but only go ahead and buy if you want to commit to a particular train on the schedule.

Note that a Saver Day Pass, in contrast to the Super Saver Ticket, is good on ANY train on the route that day. Still tied to a particular date, ut not to any time. So where the cost of a regular ticket is over 52 CHF ( such as Montreux to Luzern) a Saver Day Pass is a good buy. Note that they start low and the price increases, so it is good to buy them a few months in advance if your dates are firm.

https://www.sbb.ch/en/tickets-offers/tickets/day-passes/saver-day-pass.html

I would particularly recommend buying a Saver Day Pass for the day you travel from Luzern to Lugano. That way, you can decide at the last minute between taking the fast route through the long and deep tunnel, or the scenic route over the Gotthard Pass. For that, you take the Treno Gottardo, which departs Luzern at 9:18 or 11:18, etc., and change trains at Bellinzona. Otherwise you end up in Locarno ( which is a nice place to be).

With the Saver Day Pass, you also have the option of riding a boat down the lake from Luzern to Flüelen, and boarding the Treno Gottardo there. We did that last year and everyone loved it, especially the boat trip.

Another thing to pay attention to is the route. That 37.50 CHF (and that is the half fare price) is for a route using an IC train to Olten, followed by a regional train to Luzern. It is the fastest way, but not necessarily the most scenic way. If you specify via Zweisimmen and Interlaken Ost, you will be on the scenic Golden Pass route. Takes longer, but quite scenic, and the half fare rice is 40 CHF.

Most importantly: Don't overthink this. How many months in a advance would you buy tickets for the New York Subway?

How do Swiss travel by train? They go to the station. Buy a ticket, and just board. It is not complicated in the past we bought tickets from the ticket window. Then ticket machines came, and nowadays most tickets are sold via the smartphone app.

If you do more than a few trips it is worthwhile to get the Half Fare Card. Most Swiss have one. This halves the prices. You still mostly buy tickets ad hoc, on the day of travel itself.

Supersaver tickets, and Saver Day Passes may be offered if you do the un Swiss thing of booking tickets far in advance. The Half Fare Travel Card further reduces the price of those. If you are getting the impression that the price for a Supersaver ticket is the same with and without HFC you are doing something wrong during your research.

My advise: Do not worry about tickets now. May is half a year away.