Not to pick on you specifically, but I tend to agree with other posters that testing (automated or otherwise) is just an element of programming. Like all elements it needs to be done to taste, but it's pretty essential.
A line of questioning: Do you have time to write clear code? Time for comments? Time to manually test your changes hundreds of times? Time to refactor existing code when adding new code? Time to remove dead code? Time to automate the testing while you still have the little state machine you are working on in your head? Time to add observability to spot performance issues? Time to consider your rollout plan? Time to keep on top of changes which are in use? etc...
Automated tests (including unit tests) are just one part of writing correct code. If you are asked, "How long is it going to take?" that implies finishing all aspects of coding required to get something correct into use. You prioritize that, not anyone else.
A line of questioning: Do you have time to write clear code? Time for comments? Time to manually test your changes hundreds of times? Time to refactor existing code when adding new code? Time to remove dead code? Time to automate the testing while you still have the little state machine you are working on in your head? Time to add observability to spot performance issues? Time to consider your rollout plan? Time to keep on top of changes which are in use? etc...
Automated tests (including unit tests) are just one part of writing correct code. If you are asked, "How long is it going to take?" that implies finishing all aspects of coding required to get something correct into use. You prioritize that, not anyone else.