Polling relies on sleep. Setting the polling time matters a great deal, because you'll almost always take at least one poll interval to discover that something

Polling relies on sleep. Setting the polling time matters a great deal, because you'll almost always take at least one poll interval to discover that something has come up, and on average every polled step in your startup process adds (poll time/2) to your total start-up time. If you have a bunch of steps that require polling, that adds up fast. The problem is often relying too much on cold-starts; these polls amortize well in a real system, where you can afford (and want to afford!)