Speeding up your Build & Run (F5)

Have you ever been in the situation where you need to run your application, check something, edit some code, build, run again, repeatately? And each time you are pressing F5 run run, it’s just taking too long to build.
There are many ways to improve the build time (including buying cool and speedy hardware like an SSD drive), but this one is free:
In Visual Studio, select Tools –> Options --> Projects and Solutions –> Build and Run

Check the “Only build startup project and dependencies on Run” option.
I can’t believe that this is not a default setting.