Not long ago, it was taking Energy Australia nearly two weeks just to get around to logging my reports, and then a further two weeks to send someone out with a paintbrush to clean things up.
Now, they are logging the reports within 4 days, and cleanup seems to happen within 10 days in many cases, giving a 2 week turnaround time.
The problem with this is that I read an anecdote not long ago that said if you cleaned a site within 2 days, there was a 90% chance it would remain clean. If you took longer than two weeks, there was a 100% chance of repeat graffiti.
What I have noticed over the last year though is that although Energy Australia kiosks are still being hit, they are being hit much less often and the volume of graffiti is much lower. Cleaning seems to discourage a lot of vandals. Not all, but many. Which is better than nothing.