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I once heard that if you spend 90% of your time developing the design of your program the coding part will only take a trivial 10% of the time. I have found a lot more success in spending about 30% of my time designing the architecture than when I used to spend 0% in design. As a result my programs seem to avoid unnecessary coupling and are now more flexible to change before any re-factoring takes place.
I usually finish the design phase once I have a clear idea of what all the objects should be named (I am really picky about naming objects) and what single responsibility each will have. Once I feel confident in my design and feel ready to start constructing the software, would there be any benefit to taking more time to keep re-thinking the design? To me it might seems like it might be overkill.
What's an effective design to code development time ratio and should the design time be greater than the code development time?