Updated: Dec 2, 2021
This post aims to cover as many aspects relating to development cards as possible. In the base game of Catan, there are a total of 25 dev. cards, most of which are Knights (14). The second most popular dev. cards are Victory Point cards (05); meanwhile, the three other ones - Monopoly, Road Building, and Year of Plenty have 02 cards of each kind. Now we shall talk about them one by one.
Victory Point cards are the most braindead, yet the most cost-efficient way to earn VPs (only 03 resource cards for 01 VP). In general, you will have a 20% chance of getting one when purchasing a dev. card. Depending on the situation, drawing this type of dev. cards can be considered lucky or unlucky. Since VP cards cannot be flipped face-up until the end-game, there is pretty much nothing to do with it other than bluffing your opponents. That part will be discussed later at the end of this article.
Knight cards more than 90% of the time yield 01 resource, however, that is not always the true value of them. Aside from giving you a resource card immediately (sometimes it does not), it also helps keep the robber (if any) out of your business while preventing one or more of your enemies from collecting resources. More importantly, on many occasions, it is wise to flip a Knight face-up before the dice roll to increase the number of cards in your hand, allowing you to hold on to your precious combination of resources in case you have to discard half of your hand due to rolling 7. Speaking of number 7, that is also the number of Knights required to turn your 02 "soft" VPs from the Largest Army "concrete". And last, if there are two players attacking each other with Knights, the one that takes his/her turn right after their nemesis will have the upper hand.
Monopoly cards, in my opinion, are Knights on steroids. Although they do not block any hexes, they rob every card of the resource type that you declare, which can potentially be as many as 19. For those who wonder, 19 is the maximum number of each resource. If possible, before activation, you should try to trade away the resource that you are about to declare. Additionally, to ensure a successful Monopoly, you can legitimately count the number of cards in the bank as long as you do it publicly. Most of the time, Monopoly is best to be used after rolling the dice; howbeit, in a few rare cases, you might need to activate it before the dice roll to stop others from discarding all the cards of the specific resource you need in case you roll 7.
Road Building cards: No other development cards are more straightforward than Road Building. Despite its very niche effect, this type of dev. cards has the highest value when the drawer is a pure Ore-Wheat-Sheep (even Ore-Wheat) player. By providing 02 instant roads, it makes space for them to build up to 02 more settlements or to steal the victory in the most unexpected fashion - taking over the Longest Road while they have already had the Largest Army. One fun fact about Road Building cards is that they are the only type of dev. cards that can be completely useless, either by running out of roads or being completely zoned by the others.
Year of Plenty cards are deemed the least impressive among the three rare dev. cards by many people. Apart from the flexibility, the type of dev. cards neither provides an enormous number of resources nor disrupts enemies' gameplay; however, that is only the surface. In fact, Year of Plenty involves in many high level plays such as using it to waste key resources in hand before ending your turn (in case you get robbed), or trading the 02 resources from Year of Plenty to earn even more resources (for example, 02 Ore for 5 Sheep while you have a Sheep port). Moreover, the rarest and most advanced usage of Year of Plenty is activating it before the dice roll to lower the number of resource cards left in the bank down to below the minimum requirement for distribution.
The art of bluffing is the key factor to be a master in playing dev. cards. You can actually interact with people, changing their plans without even flipping your dev. cards face-up. Letting people assume that all of your unused cards are Victory Points usually leads to you catching them off guard later on. Reversely, acting confidently as if your face-down Victory Point card is a Knight sometimes prevents people from putting the robber on you. Besides, faking a Monopoly by counting cards in the bank might leave a big influence on your opponents, discouraging them from stocking multiple copies of the same type of resource in hand. Ultimately, making your competitors think that you have either a Road Building or a Year of Plenty up your sleeve oftentimes deter them from building toward your nearby spots, reserving those for your expansion.
Thank you so much for reading this lengthy article. If there is anything about dev. cards that I forgot, please remind me in the comment section below. Also, I would be extra grateful if you could drop a like and share my piece of work on your pages. See you next time.