You can never have too many spares, but I found it relatively easy to get starters and alternators rebuilt even in fairly
remote areas. Of course, that could mean you still have to sail a few hundred miles to get someplace with
repair facilities. Obvious stuff includes oil filters, fuel filters, oil, coolant, belts, impellors, all different sizes of hose clamps, Here's the thing someone once told me. Carrying lots of spares just means that something else will break that you don't have a spare for. I have found that to often be true, but luckily there is almost always another cruiser around with the right spare and/or the skill to come up with a jury rigged solution. Carry tons of tools--you almost can't carry too many. They will allow you to
work with whatever you do have. For example, I had a fuel return line fitting crack, spraying hot
diesel in a fine mist all over the place. I didn't have a replacement for the specific
compression fitting, but I was able to clamp the part together using a very small vice grip. That jury rig kept me going all the way from the
Bahamas back to
New England where I could order the part. Similarly, I've used silicone tape to heavily wrap leaking hoses and fittings, including a leaking
fuel pump complete with a small hose clamp holding it in place. Carry various sizes of hose and various PVC elbows and you can almost always make some replacement hose, even for the molded ones. Auto parts stores also carry molded radiator hoses, and you can often find one that will
work if the store will let you hunt around.