I would almost always have to go with "no, I don't have time, sorry". But even so, there are a lot of jobs or contracts where unfortunately things are basically

I would almost always have to go with "no, I don't have time, sorry". But even so, there are a lot of jobs or contracts where unfortunately things are basically structured so you really can't just refuse requests and keep the contract. But for people who have good savings and backup plans in case they are fired, it could be really helpful. Setting aside the exact content of the message, part of the idea at least is really critical. It is really hard to say no to a request. But oftentimes the success (or quality) of one or more projects can depend on it. These types of interactions where scope is negotiated are probably the hardest part about software engineering and also possibly the most critical. If I am truly honest with myself, probably almost all projects I have done have been stretched past their real budgets because I felt I had to fulfill some request that was not a real requirement.