Specifically, I've found that many buildings only need labor long enough to emit workers. Inspectors, water carrier, lumberjacks, shrines, music school, even smelters and farms continue to work if you turn off the building after they've left.
For example, a Logging Shed requires 14 employees. But I can staff 3 logging sheds (and more) with those 14 employees by turning of one shed as it ejects workers and turning on the next one. I can staff many inspectors towers with 5 employees by having only one turned on a time.
Some observations:
1) For many buildings, its no big deal if I don't turn it on as soon as the laborers return, so I don't panic if I'm a little late. I get pretty close to max production out of my logging camps even if they idle once in a while because the amount of time they idle is small compared to the amount of time the workers are out working.
In fact, I turn on some buildings (Well, Herbalist, Inspectors Tower) only when needed.
Of course, be careful with Inspectors; don't wait for a building to get into danger.
2) However, you should wait for the worker to reach his destination before turning off the building. If you turn off the Logging Shed before the lumberjack starts chopping his tree, he might disappear. But I haven't seen a lumberman disappear once he started chopping.
3) Some building laborers return to their building so often that its a lot of work trying to keep up. Farms specifically. Of course, you shouldn't be farming until you have excess labor and money anyway. 4) Don't do this with some buildings. This just doesn't seem to work with Fishing Quay. Turn off the building and the boat disappears even when it is activily fishing or returning with fish. Taxes aren't collected if the Admin City is turned off, even if the tax collector is still walking. But I think the Tax Office itself can be turned off once the collector is walking. I think. 5) Some Industrial buildings (Kiln, Clay Pit) don't eject workers, but need constant labor to work. Turn off the labor and work just stops. However, the Smelters and Stone Works buildings are both worlds. They need constant labor to smelt or cut blocks, but if they don't have enough resources to be smelting or cutting blocks, you might as well turn them off while the gatherers are out getting the raw materials. This is especially useful in the first year of your city. 6) The only way I've found to do this with Commerce buildings (which can't be turned off) is to adjust my global labor allocation and run short of laborers. A warehouse or mill really doesn't need full staff while the city is small and growing. I'm sure I'm not the first to make these observations, but I couldn't find a thread discussing this. So I wanted to throw my observations out for comment. DJ