Merchant's starting : Usually at the start merchant would be easier, as captains is very cheap. Most things are also very cheap. NPC treasure hunting are a thing to do at this stage.
Pirate's starting : Usually at the start they need to gather voodoo like HNs and FoJ for raids, they also have the choice to do half merchant and half piracy.
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Merchant's Mid Point : This is when we would have a hideout and a good income. Captains on this point on becomes fairly expensive. Raids attacks becomes more common. A way to decrease loses becomes a must have, protection is a secondary.
Pirate's Mid Point : This is when they start using common tech to increase plunder with the money they earn as they don't have to invest the money into captains like merchants do. This is also when capturing expensive ships is something they would do.
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Late-point Merchant : This is when banking and and Gold Trading becomes a common. Captains at this point becomes too expensive, so most would start using the voodoo "Bribe", protection like MindBar would become a 24/7 thing. When hit, their loses are very high, so most would depend on protection at this point. Has 800+ ships in trading, has a large voodoo chest. Etc.
Late-point Pirate : This is when capturing ships become common, and hitting merchants with 800+ ships in trading is a thing they would do. Has a large voodoo chest, most plunder tech would have be fully upgraded. At this stage its end goal becomes to become a collector of MOW, buries most money in ground or as gold bars, as bank are no longer safe, starts building their own bank for storage. Etc.
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End goal for merchants : Own the most money and has the most influence, be a king of a lot of nations. Etc
End goal for pirates : Has a lot of fame, owning a port becomes a common goal, for the reason of fun. Have lots of expensive ships. Unlock all tech. Etc.