If by vacation you mean an extended break from the stresses and responsibilities of your daily routine, then the answer is yes, you definitely need a vacation. Very few people can function effectively at their jobs or homes without taking some sort of relaxing diversion once in a while. Vacations allow us to regain some perspective on our personal lives and re-evaluate our priorities when it comes to a work/home balance.
If by vacation you mean planning an elaborate get-away with a spouse and four children in tow, however, you may want to consider the higher purpose of vacation time. Some people whose vacationing reaches exceed their grasps may find they need a vacation from their vacation. Any vacation plan which requires the precision and logistical planning of a military operation may not be such a good idea unless the benefits of the destination outweigh the sacrifices necessary to get there in one piece.
Some people choose not to take advantage of paid vacation time in order to add those funds to their personal income. While this may make some financial sense, it can also lead to a number of stress-related illnesses and conditions, such as ulcers, depression, and general anxiety. Some dedicated or work-fueled employees may not want to take advantage of all the vacation time they have accumulated over the years, but a few days spent away from the job can help minimize the effects of work-related stress in the long run.
If you feel you are in need of a vacation, timing can be everything. You may want to plan your vacation when there is a planned slowdown at work or during an extended break for schoolchildren. Spouses may want to coordinate their vacation times in order to enjoy a mutual trip out of town. Some people may have to work even harder before a planned vacation in order to minimize the effects of their absence. By planning a vacation at a convenient time for employers and house sitters, you can spend more time relaxing and less time worrying about the job you've temporarily left behind.
Many people realize they need a vacation whenever the routine of work or home starts to affect their mental or physical health. When the thought of going into the workplace the next morning becomes a trigger for anxiety at night, it may be time for a vacation. Feeling as if you are simply "going through the motions" or putting in minimal effort at work or home is another sign you might need a vacation. No one enjoys being stuck in a rut, and a pleasant responsibility-free week spent on a warm beach or on a cruise ship may just be the thing you need to break out of it.