Depends if you value your time more than minimum wage. There is certainly a time and a place for everything but I don’t really feel like being responsible for something that costs the $N a month managed. Sure I could do it myself but my time is worth more.
When you think about it, ideally most managed services have found some natural price for their services that helps make the above logic work. And if it does not, it might be actually overpriced. I suspect a lot of folks that say roll your own are undervaluing their time.
