roadworthy certificate how long does it last

Short answer: it depends on your state, because of course it does.

In Victoria a Roadworthy Certificate is typically valid for 30 days; in Queensland a Safety Certificate lasts 2 months or 2,000 km for private sellers, and 3 months or 1,000 km for dealers. NSW’s eSafety check (pink slip) rides for about 6 months. The ACT inspection report generally gives you around 42 days.

SA, WA, TAS and the NT generally don’t require a roadworthy for private sale transfers, though inspections can be ordered and any issued paperwork will state its own expiry. Always check your state authority’s latest rules before you get caught out at the counter.