When is it better to collect money from a node instead of transferring it? [duplicate]
This is a very complex topic and even among advanced players it usually comes down to just checking, which is more profitable. Especially as the trade system often receives significant changes.
The general mechanic is, that each node transfers trade power(and money) to the next ones in the line. A nodes trade power depends on the power received from the incoming nodes and the goods produced by the provinces within the trade node in question. Collecting in a node will convert part of your trade power to direct income(half to be exact, the other half is lost), sending it along provides a bonus and allows you to specifiy where to send it.
You always automatically collect in your home node, so in general, if you are able to have a good chain of trade power from a node to your home node, you'll earn more money by transferring. Several nodes are end nodes(e.g. venice), which don't send trade power along(no outgoing arrows on the trade map), so transferring in one of those is pointless.
If you can't build up a good chain from your most profitable trade node to your home node, you are usually better off collecting.
But as I said, it's much more complex than this. Factors like the trade goods produced in the provinces, the actions and status of rival nations (size, fleet, merchant use, embargo), the position of your light ships and trade companies all make this a very deep topic. There is little harm in just trying both options and finding out what's the more profitable one this way.
In addition to the previous answer, which is correct, here is the short version: Collect in non-home nodes only in the following case:
you can't build a chain of transfers from the desired node to your home node
After you take into account the penalty for collecting in non-home node you still have enough trade power to outcompete other nations in the target node
In the end you receive more money compared to any other consecutive chain of transferring merchants that leads to your home node.
Examples:
you play as Venice and conquered all the Mediterranean, then it's very profitable to also collect from Genoa
you play as France and murdered Savoy and the Low Countries, then collecting in both English Channel and Genoa is VERY profitable
You're colonizing India and Oceania as England, but Arabs block your trade through Egypt and Portuguese take all the trade in Seville, then it MIGHT be more profitable to collect directly in India