That continues the analogy -- it doesn't rain often in the desert, but almost all deserts receive rain. And since it rains so rarely, you're certainly not going to find an umbrella during the rainstorm.

So again, if staying dry in the rain is important to you, buy an umbrella before the rain, if you don't care about getting wet from time to time, then no need for the umbrella.

While the personal blog owner may not care about DDoS related downtime, he may face extra usage charges due to higher bandwidth, CPU usage, etc that he'd like to avoid.