I know of people saying the only thing they don’t like about Myki is the requirement to touch-off. This is particularly a problem at suburban stations in the evening peak. Some stations end up with queues due to inadequate numbers of readers.
There are three main situations where it doesn’t matter if you don’t touch-off. That is, you will end up paying no more.
1. Myki Pass, on trains, trams or buses, most cases
If you’re on a Myki Pass (eg a weekly or 28-365 day pass, the equivalent of a Monthly or Yearly) and your trip started in a zone covered by the Pass (eg it’s your usual trip), the default fare is $0.00. You’re not going to be charged any additional money if you don’t touch-off.
2. Myki Money, on Metro trains, if your trip was zone 1+2
The default fare (what you get charged if you don’t touch-off) is a Zone 1+2 2-hour. If that’s the appropriate fare, then you’re not going to be charged any additional money if you don’t touch-off.
3. Myki Money, on trams, most cases
This is the one everybody should know about, because it’s been publicised a fair bit, but you still see people needlessly touching-off on trams.
The default fare on trams is a Zone 1, 2-hour fare. This is the appropriate fare for almost all tram trips. You don’t need to touch-off. The only exception is if your trip is within the zone 1/2 overlap (on routes 86, 109 or 75) and you specifically want the cheaper zone 2 fare.
The mantra is “touch on, touch off” — because that’s the easiest thing to remember. But for regular passengers, if your normal trip falls into one of the above categories, you may be able to save yourself a bit of queuing/hassle.
PS. Note that if you don’t touch-off, it’s at the next touch-on (which might be the next day) when it charges you for the previous trip, and displays that amount. This can confuse people at first.
(I’ve written on this topic before, but arguably that post was too wordy, and right now a lot more people are coming onto Myki, so it’s worth revisiting.)
Source: Myki: Default fares