You'll need to renew:
* Medical. Class 1 needed for commercial ops, Cl.2 for private.
* Aeroplane Flight Review aka BFR. unless you do some other qualifiying thing eg a flight test for something, so...
* After 1 year from the last IR test you no longer have an Oz instrument rating so will have to renew it.
IF it has lapsed for NO MORE THAN a year then you can do a renewal flight test. It's bit easier than the initial, not as long & can use a synthetic trainer for part of it so is cheaper.
IF it has lapsed for less than 5 years then you'll have to do an initial issue flight test.
IF it has lapsed for more than 5 years then you'll have to do both the IR theory exam AND the initial issue flight test.
* Instructor rating: Valid for two years so must renew with a flight test after this period . If you have Multi training approval there is no specific requirement to do the renewal in a twin.