Unless you're wanting to run a high power stereo there's no good reason to "upgrade" to 12v. A 6v system with a good battery & starter with clean connections & properly sized cables will start just fine. Having said that back to your original post, if you don't crank for extended periods your starter will be just fine.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.