I am not putting anything aside. My employer is. My time is a resource my employer has at his disposal. He pays me and in exchange gets to decide how he wants t

I am not putting anything aside. My employer is. My time is a resource my employer has at his disposal. He pays me and in exchange gets to decide how he wants to allocate my time. My job includes giving realistic estimates on how long things take to accomplish. When asked to do something that I know cannot be done due to resource and time constraints, I's my duty to tell my employer as much, so he can make a strategic decision. And in my experience, employers value that input.