Being busy seems to be in fashion as evidenced by how proudly many people proclaim they are too busy to get everything done. News Flash: Just because you have a lot to do, you are not too busy for more work. Got it: you can’t do everything, but you can do the right things. You have to prioritize your work. Being busy is not good in and of itself. If you are performing manual labor, being busy is good; it means that there is work to be done and you will have more hours you can charge. In the realm of knowledge work being busy does not mean you are being productive. You likely have become an unwitting victim of Parkinson’s Law.
If someone asked you what you are paid to do, would you answer, “I am paid to be busy”? Of course you wouldn’t. Why do you go around saying with pride that you are busy, when that’s not why you’re paid? If it is so that you don’t get extra work, you are just preventing your career from progressing. Extra work is a sign that you are ready for more work and more responsibility, which usually means more pay (and if it doesn’t, it means when you find a new job where you can get more pay). You are paid for results.
Since you are after results, when you get more work assigned, you have to triage it. Where does this new project fall into your priorities? Some work will not make this cut. This is the work you are “too busy for”. In actuality it is work that would detract from other, more important work. If your boss has assigned you work you feel is out prioritized by your existing work, you need to have a conversation with him and get proper priorities. It often means you are spending too much time on important, but not that important tasking.
If it does make the cut (and this is the default answer for tasking from your boss), then you have other work that will have to be put on hold, delegated to one of your direct reports (if you are a manager), outsourced, or that will simply stop being done. Some work may be taking more time than it needs, and the addition of extra work meant you stopped allowing a task take up more time than it deserved. You will not know until you have to make the decision on what gets done.
If it is possible to do the new task in addition to the old, then you weren’t as busy as you thought. Either that or you were being busy instead of being efficient or effective. In either case your prior understanding was wrong. As you improve your skills and abilities, you will become more efficient and work you were too busy for a year ago you now have or can make time for.
You are not too busy for extra work. You are either less efficient than you can be or you are working on less effective projects for you.