I'm working as a QA for software product development. During the course of our meetings we typically discuss what tasks we are going to do and provide an estimate for each task. My manager has a habit of loading us at 100% for the tasks. For example, if I work continuously on a task the entire day I can do it in 2 days. So I give my estimate of 3 days. But the manager reduces the time span to 2 days or less. The result is that I'm usually working continuously to finish off things.
Now I have heard that normally at work we have times of high work pressure and times when there is less of it. The problem is that the latter is never true for me. Even after a product gets released there are more and more things to do. So I end up constantly working at either 100% or more. This affects me negatively because I don't get time to learn anything new or improve myself as I'm just meeting one deadline after another.
I discussed this with my manager and he tells me "that's how it's going to be, work will always be there". Now my colleague is okay with working late quite frequently but I don't want to do this. I do not want to jump to another company as sooner or later it will happen again. I need to learn to manage this. What can I do in this situation?