These are listed in decreasing order of ceremony. You can find "real" developers, somewhere, using all four of these.
A better question might be, at least in this community "will UML be useful for my startup". My answer to that question is "check out state diagrams and sequence diagrams and leave the rest behind" and use some form of Data Flow Diagrams.
In a very young project, it is likely that you will need to throw out the code you have written and start over. The less ceremony (translating to time) you put into the stuff that you throw out, the better off you are. If you are working in a category 5 CMM outfit, then that is a whole other story entirely.
By the way, methodology #4 (JSC) is Just Start Coding.
1. Waterfall 2. UML/OOA&D/RUP/Iterative 3. Agile 4. JSC
These are listed in decreasing order of ceremony. You can find "real" developers, somewhere, using all four of these.
A better question might be, at least in this community "will UML be useful for my startup". My answer to that question is "check out state diagrams and sequence diagrams and leave the rest behind" and use some form of Data Flow Diagrams.
In a very young project, it is likely that you will need to throw out the code you have written and start over. The less ceremony (translating to time) you put into the stuff that you throw out, the better off you are. If you are working in a category 5 CMM outfit, then that is a whole other story entirely.
By the way, methodology #4 (JSC) is Just Start Coding.