I call this *skill*. You need a lot of experience to understand tools/technologies that you use. Know their weak spots and advantages. You even need to know the developer experience, and how good it will match your diverse team. Not mentioning documentation, support, and community.
On the other side, if I just read some hyped blog post about some FitAllTheInternet cloud database. It charges me only for GB and CPU time, and does it monthly. It suits my needs and will suite them later. Moreover, I have the solution from now on. It may be overkill, but it may be a convenient overkill. Also, I definitely will go stressed with putting additional info about hardware caveats and Postgre. And when I will have 7,800 employees, I will go back, rework, and reduce the costs.
Just kidding. Investigate alternative solutions anyway :-)