I've had some circumstances where it has been wiser. It's very rare in the Classic version, but when Austria or France are in a stalemate that requires fleets to break, it is sometimes better to postpone the build for a year so you can have a second fleet as opposed to building a redundant army.

It might conceivably come in handy in other maps/build rules when a critical outpost was taken in Autumn and could be reclaimed in Spring where the alternative is to build on the other side of the board [England in Colonial Diplomacy as well as occasionally beach-heads in Aberrant and Build Anywhere Rule sets]

hm there is games where it's good to postpone a build.
example: you are russia on standard map and have an alliance with turkey but the others block everything and your only way out is to go through the northern seas and you have 2 builds: build in st petersburg nc postpone one and build in next year

the example is just out of when I used it once but there is more of this like france in marseilles on france against austria 1on1 or whatever... :)

I used Rox's example in a game. Generally the reason I don't build is because I need more fleets and I have limited fleet builds. Additionally, it could be a bargaining chip. "I'll ally with you if you keep your units down below a certain number," &c. If you're worried about your ally becoming overwhelmingly strong.

There are plenty of good reasons, but my favorite is that a waived build is a nice deterrent against being stabbed. For some, the general rule of thumb is that a stab should render the stabbed player incapable of retaliation. A waived build minimizes this part of the equasion nicely. It works best when you have an ally that you don't really trust. It can demonstrate trust on your part, but not weakness.

Good ideas, everybody. Follow up question; Is the build prostponed to the next build season, or can you use it immediately, even if it's a diplomacy/move season?

It's waived til the next build season. I really like waiving builds in the midgame, as it's a great stab deterrent and it gives you a great shock tactic when you need it. Opponents rarely notice that you have a build or three in hand, and when you take no centres but suddenly pull in 2 new armies and a fleet against them, it can be quite a game-changer.

Nice.

Have I mentioned that this is the best game ever? I wish I were better at it.

Time and patience. Skill comes with experience, and experience with time.

whiskeyandfeet
you are so rigth
this game is the best i also wish i was better at it

I sometimes waive a build if for example I have too many armies and want fleets, but due to circumstances, don't have enough coastal SCs. If I can't be sure of continual growth I postpone the build till the next build season and build the fleet then. And visa-versa for armies (although this is less often the case.)