Redundancy.

Redundancy is back up. What will you do if something fails or is lost overboard. Your VHF or your anchor.
Coastal sailing with crew will require less than offshore solo. However, I suggest everyone needs backup for the following

• Anchor. If you lose your anchor (easy to do) you’ll need a second. A second anchor can also be a big help in making certain anchorages more secure/comfortable.
• Steering. Most yachts (with wheels) have an emergency tiller in case the steering linkage fails. Make sure yours works.
• Bilge pump. Stay safe and make sure you have a back-up bilge pump or at a minimum a bucket and crew!
• Battery. Your starter battery and your house batteries should be independent. Ideally having some way of linking the two together to boost the starter battery if it runs low on charge.
• VHF. Hand held VHFs are affordable and useful to take in the dingy or grab bag.
• A means of navigating. This might be paper charts and handheld compass or a second electronic navigation, eg Navonics on a tablet. Or both!
• Spare fuel in a safely secured fuel can. 10-20 litres.