Re: Handy to have spare parts
Some other (perhaps obvious) spares. I would include any spares for essential systems that can keep the boat going:
Spare sails and sail repair kit (I carry an old spare main and 3 headsails)
Plenty of line, blocks etc.
Spare stay and fittings (long enough to replace your longest stay)
Engine impellers, belts, filters, oil, spare hoses etc.
Spare alternator (automotive will do)
Good electrical kit with different gauge wire, connectors etc.
Rebuild kits for pumps aboard
Handheld GPS with extra batteries (and paper charts)
Tools, tools, tools so you can fix anything yourself
Basically, spares for any of the essential systems so you (hopefully) never have to be stuck somewhere waiting for parts to be able to sail the boat. This gives you the luxury of choosing when and where to stop the boat for repairs and maintenance.