Fuzzing isn't really a "2-3 times longer" thing. You have to set it up once (which for basic fuzzing is quite easy), you throw compute power at it, and it turns up bugs for you. As you make changes to the project the fuzzer will explore new paths mostly automatically.
You may want to spend some time looking at code coverage and doing some of the advanced things outlined in this article, especially for very high risk / reward projects like Curl, but even that is not a lot of work.
You may want to spend some time looking at code coverage and doing some of the advanced things outlined in this article, especially for very high risk / reward projects like Curl, but even that is not a lot of work.