Setup time depends on the complexity of the décor and the number of people working on the installation.
For very large events, setup can take many hours. When we decorated the grand opening of the MCI Arena in Washington, we worked close to 24 hours. We have also done major fundraising events with large-scale décor that required nearly a full day of preparation.
On the other hand, we have also completed smaller installations in very short time windows. In one case, we had only about one hour between the previous party and our event, so we brought a large enough team to complete the work within that time.
In general, we prefer not to accept setup windows shorter than two hours whenever possible. When there is very little time, even a small problem — a locked entrance, an elevator delay, a power issue, or a loading problem — can create serious pressure. The best protection against those problems is having enough setup time.
If it is absolutely necessary, we can sometimes work within a very short window, but that extra hour often makes the difference between a stressful setup and a smooth one.