I believe that planning succeeds better than just ESP. If you need parts, you always need to have at least two suppliers for each part and hopefully three or more. Why? Just for the reasons you stated. In a crunch, you need options. If you have a sorted list of suppliers, you can quickly find a replacement source for a while if your primary source experiences unexpected difficulties.
It is all about good risk management and planning.
Just my opinion.
Replay available now: A handful of emerging network technologies are competing to be the preferred wide-area connection for the Internet of Things. All claim lower costs and power use than cellular but none have wide deployment yet. Listen in as proponents of leading contenders make their case to be the metro or national IoT network of the future. Rick Merritt, EE Times Silicon Valley Bureau Chief, moderators this discussion. Join in and ask his guests questions.