Hi Chanahpat, and welcome to MySwissAlps!
There is only one way to know for sure: add up the full-fare cost of all trips you intend to do by train, bus, cable car and boat and compare the total cost of separate tickets with the cost of doing the same trips with the Swiss Travel Pass, Swiss Half Fare Card etc.
You can find fares in the Swiss Timetable.
It is important to be aware that the fare shown for any trip in the Swiss Timetable defaults to half fare, as most Swiss residents will have a Half-Fare travelcard which entitles them to this discount. Your calculations need to be based on full fares, which are double the default fare that comes up.
There is information and a spreadsheet here to help you:
www.myswissalps.com/tr ain/ticketspasses/prac tical/chooserailpass
If you can't be bothered doing the calculations, and will be out and about each day using trains and mountain transport or boats, an 8-day or 15-day Swiss Travel Pass might suit you.
If you get an 8-day pass, you will need to consider another solution for the additional days e.g. point-to-point tickets, or a Saver Day Pass (for example).
Even if you don't use all 15 days of the 15-day Swiss Travel Pass, there's still a chance it might be your best option. An 8-day second-class Swiss Travel Pass costs an average of CHF 49.75 per day. A 15-day second-class Swiss Travel Pass used for 10 days costs an average of CHF 48.50 per day.
If you want an easy and convenient solution, I would probably go for the 15-day Swiss Travel Pass. If you want the most economical solution, you need to formulate a detailed itinerary and do the sums.