Tyres
Your tyres affect safety, fuel efficiency, handling and legal compliance, so they're worth checking properly before a long drive. Look at tyre pressure, tread depth, and any signs of uneven wear or damage.
A simple way to check tread depth:
The legal minimum tread depth is 1.6mm. An easy way to check this at home is with a 20p coin. Insert it into the tread grooves. If you can't see the outer rim of the coin, your tread is fine. If you can see the rim, it's time for new tyres.