I always double my estimation:
If you do so, your boss may ask why and could you reduce the estimated time. How would you response them?
You reduce the task requirement, you cut down from the business logic, otherwise you cut from the product code quality which will lead to longer future task durations and bugs, which leads to less profits, and noone wants that.
Haha. But usually, requirement is not very concrete
Sorry then, you can always change your job, work with smarter product owners :D, preferable in-house products, SASS and technical managers.
Or build something random which u think it requested, and if is wrong estimate a new task.
You add time to write tests?? Strange.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.