I have a scanner, and regularly scan in the Adelaide Hills. Lots of the stuff I get on the scanner is rubbish, but every now and then there is gems of information.
The Goodwood work has meant that track controllers have been talking to each other from Belair and Mile End.
What area would you be scanning?
The way I saw it when I bought my scanner was that I should buy it now, or else I miss out on an important part of trainspotting which is about to become a memory. I parted with about $100 or so and bought myself a beginner Uniden BC72XLT scanner, and I must say that I am impressed when I am at places such as Dry Creek.
To be honest my scanner gets very infrequent use (once a month is an optimistic guess) and if the ARTC swap over there signals, well that's too bad, and I will then give my scanner to someone else who may have a use for it. ARTC said they were turning off their signals ages ago, but I bought my scanner in May last year and it still worked alst time I used it.
Also, if you want to buy a scanner, check with any local media companies. My local newspaper company were getting rid of their scanners, and I found out too late. If I had knowen earlier, I would have been able to get one through someone I knew who worked there.