Silly example i made up on the spot, but not too far from real life. I'm iterating a list of 10000+ objects with about 20 or more nested properties. Some times

Silly example i made up on the spot, but not too far from real life. I'm iterating a list of 10000+ objects with about 20 or more nested properties. Some times one of them behave strange. This function runs several times per second. Option1: Print all of them, requires rebuild, would log 200000 lines every second. Unless i wrap the print inside conditions, requiring yet another rebuild. Option2: Conditional breakpoint: user[i].department.balance <= expected_value. Bang, i can now inspect both the complete nested user-object, and the previous/next item in the list, other local and global variables, the call stack of how it reached there, the state of all other threads in this moment, and so on. With the really good debuggers like .NET or JVM I'm even able to rewind the execution pointer to the start of the function or hot-swap the code as it's running. In short, a debugger allows you to see all state of the program at once, and you can retroactivelly choose what is relevant. As opposed to printf where you must select upfront. Maybe even more importantly it's lacking stack traces, unless you add a log and request-id at every function-enter/exit. There is also the case of third party code which you can't edit to add printf to. Many environments usually by default give you pretty good context of the symbol names or even complete source code which you can step through (except c++ land where you'd need a debug-build of the lib, which isn't impossible either).