Many people can use patch notes or Dev announcements to invest smart in long term speculation on things that are gonna change and make a ton of isk with the changes (ex: gila, mineral and BPO changes). Other variation is a short term speculation, trading incessantly new items put in the market and make huge profits before those items become common (I can remember the gnosis giveaway or the insertion of T3 dessys).
I personally usually stay away from both forms of speculation due to one simple factor: I’m lazy. Once again for in order for the speculation to work you need to make the proper moves, at the proper time. Long term speculations requires some ISK capital to be invested and tied up until the changes occur and it might take some time before you to manage to make a full profit, due to heavy competition. Short term speculations require you to be on top of the event as things progress and have a very narrow window of opportunity.
Actually long term speculation is somewhat compatible with my trade method, and I even would have some capital to invest, the fact that it attracts so much competition, kinda drives me away from it.
This being said, it’s still very important for traders to be aware of changes. Just because you’re not embarking the “Speculation Train” it does not means there isn’t a profit to be made. As an example I’ll talk about the recent faction armor plates changes.
Once I read that CCP was gonna buff faction armor plates, I logged in my market toons to find out that sell orders had already been bought. Someone had already bough all the faction armor plates from most markets, even though there was a low quantity of them to begin with. That someone certainly hold on to them until the changes went live and made a “quick” profit. I say “quick” because with items that don’t sell much, it might take still an extended amount of time to make decent profits. On my end, I added those faction armor plates to my spreadsheet, waited for a week until prices stabilized a bit and checked if there was a profit to be made with this “new “ item. In fact I been trading those faction armor plates myself with some profit, and even thought they sell very little, it was a nice addition to my trade items list.
Patches and item changes make, at least, a good opportunity for you to change your trade items list and adapt accordingly, even if you don’t “speculate” like myself.