Australia differs from most systems in one decisive way: a skills assessment is normally mandatory, and it is carried out by an assessing authority specific to your occupation rather than by the Department of Home Affairs. Engineers, IT professionals, trades and accountants each go to a different body, and each applies its own evidence rules.
Your occupation also has to appear on the relevant list for the visa you want, and those lists are revised. An occupation that qualified last year may not this year, so both the occupation list and the assessing authority should be confirmed before you plan around this route.