If you are trying to really quickly get code in front of users, and are working through a lot of ideas that don't end up going anywhere (code that is eventually thrown away), then heavily tested code is probably not the best use of your time.
Once you get a product with some traction, and are going to be working with a codebase for some time (especially a code base that will be growing), heavily tested code is invaluable.
Example: Upgrading a large Rails app (~250k lines) from rails 2.3 to 3.0 in eight weeks. Having roughly a 1:1 code:test ratio allows us to be extremely nimble. It also allows developers to work in almost any area of the codebase with confidence.
For apps that will be around for awhile and will be growing, a large test suite is indispensable.
If you are trying to really quickly get code in front of users, and are working through a lot of ideas that don't end up going anywhere (code that is eventually thrown away), then heavily tested code is probably not the best use of your time.
Once you get a product with some traction, and are going to be working with a codebase for some time (especially a code base that will be growing), heavily tested code is invaluable.
Example: Upgrading a large Rails app (~250k lines) from rails 2.3 to 3.0 in eight weeks. Having roughly a 1:1 code:test ratio allows us to be extremely nimble. It also allows developers to work in almost any area of the codebase with confidence.
For apps that will be around for awhile and will be growing, a large test suite is indispensable.