Whether you are Father Christmas or simply a normal passenger, from the 11th December if you board a train without a valid train ticket you will be fined 90 CHF in addition to the price of the ticket itself. This will apply to both long distance and regional trains. See the CFF website to find out more about this new ruling and the reason why (explanation in English).
On the 11th December the train timetable will also change so keep an eye out for possible new timings for your regular commute.
Don’t forget you can always buy a train ticket in advance via a mobile phone see the options here and most stations have electronic ticketing machines with the option of following the instructions in English to purchase tickets.
CFF have a comprehensive site listing the different options available for “abonnements” (travel cards) whether you are regular commuter for work or leisure.