Having the right tools can mean the difference between a quick project and a complete mess. Fortunately, you won't need too much to handle the projects here and what you will need is pretty inexpensive (certainly less expensive than hiring a plumber). You can get everything on this list for about $100, and you won't need it all unless you're doing all the projects. Where I live, that's about the cost of hiring a plumber for an hour.
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license