The criteria you must meet is as follows:
- For drink driving charges, your reading must be under 0.15%
- You must have an open licence
- You can’t have lost your licence in the past 5 years for a similar offence or because of an accumulation of demerit points
- You must also need your licence to work — it’s not enough that it’s inconvenient getting to and from work. You have to be able to demonstrate extreme financial hardship if you’re not allowed to drive.
For drug driving charges (driving with relevant drug present in saliva), there’s no percentage to worry about. It’s either in your saliva and you can apply, or you’re charged with being under the influence of a drug, which means you can’t apply.