When I went through chapter 18, my boost, Sprouts, was by far the worst to have on Arendyll, as it seemed everyone starting the chapter with me had the same tier 1 boosts as mine. I still finished the chapter in about 4 months, even though I never used more than 3 merchants. No way I was wasting diamonds on something temporary. This ended up being another situation where time boosters came in handy, and a lot of people are still doing that, as you can see from the offered trades. Any trade that has not started to decay yet, but does not have the exclamation point next to it, means that player used time boosters to get their merchant back right away. You also have to look at all trades, not just ones offering the good you want. Just like with other goods, take any trades that are asking for your good and then look at the other trades to see who wants that good too and trade. For example, I have Sprouts and someone is offering Minerals for Sprouts, but I need Ingots. Someone else is offering Ingots for Minerals, so I would trade my Sprouts for the Minerals and then turn around and trade the Minerals for the Ingots. Also, over the course of those 4 months, I never did a long-term trade with anyone, not even in my fellowship. I think the most that ever happened was swapping maybe 10 trades back and forth with another random player, who happened to be on at the same time and we just happened to be offering what the other needed, before one of us ran out of goods to trade.
@Mykan yeah, the starting amounts are really low, but as you level the main hall, the amounts go up, going from 2000 at the start of chapter 17, to 5000 after the 2nd main hall upgrade in chapter 19. And chapter 19 uses the standard cross-tier values of 1:1.5:2.25, so 5000 tier 2 ascended gets 7500 tier 1 ascended and 5000 tier 1 ascended gets 3333 tier 2 ascended. Chapter 20 is almost here, so I will get to start dealing with the tier 3 ascended soon.