I know that the benefit to paying taxes early depends on Canton, and also probably changes due to interest rates. In general they seem to give you some small interest on the amount you pay early, and conversely charge you a penalty of interest for the months after the year but before you paid. When is it worth to pay early, assuming you could have the money in a savings account instead? For example in Migros Bank there is a currently a free Sparkonto with 0.5% interest.