One of the biggest complaints about using the Opal Card is that if you change transport modes within the hour, ie from bus to train, you end up paying for both your bus and train trip, but it is only counted as 1 'journey' for your 8 journey weekly cap. The problem is even worse if you have to catch a bus then a train then another bus as you pay 3 times but it is counted as only one journey ie catch a bus from Westleigh, get off at Thornleigh station to get a train to Central, catch a bus from Central to UNSW. Sure, you are likely to bump into the "weekly day cap" of $15 for adults and then subsequently the "weekly cap" (currently $60 for adults, and $30 for concessions) but if you were using the now scrapped My Multi 2 weekly (which was $52/week for adults, and $26 for concessions) then you'd be a very annoyed person.
The Stingy Sydney solution if your tap off time from the first bus to your tap on time for the second bus is more than an hour? Register two cards and use them both in the same week. For a student, this works out as follows:
Bus from Westleigh to Thornleigh Station: $1.05 [Use Opal Card 1, Journey 1]
Train from Thornleigh Station to Central Station: $2.41 ($1.68 off peak) [Use Opal Card 2, Journey 1]
Bus from Central to UNSW: $1.75 [Use Opal Card 1, Journey 2]
Spend at least 60mins at uni....(ie Roundhouse)
Bus from UNSW to Central: $1.75 [Use Opal Card 1, Journey 3]
Train from Central Station to Thornleigh Station: $2.41 ($1.68 off peak) [Use Opal Card 2, Journey 1]
Bus from Thornleigh Station to Westleigh : $1.05 [Use Opal Card 1, Journey 4]
Repeat Day 1. By the end of the day, your Opal Card 1 will be on Journey 8 and you should use this card for the rest of the week. The cost?
Opal Card 1: $11.20 for your bus journeys
Opal Card 2: $9.64 peak / $6.72 off-peak
So the maximum you will pay is $20.84 assuming all your train journeys are all peak, or if they are all off-peak, the cost is $17.92.
How much would this have cost if you just stuck to just one opal card? Well considering you would hit the $7.50 cap every day, you would also be hitting your weekly cap of $30, so Stingy Sydney has just saved you at least $10 a week.