In our nine year old house, the spaces where the cabinets meet the drywall were caulked. After about three or four years the caulk began to crack leaving a space in this area. The space gets larger in winter - some as much as one eight of an inch - and in some places hardly noticeable in the summer as they tend to close. Is there a caulk that is "giving" enough to correct the problem? Is there a better time of the year to do the job?
The gaps you describe are not unusual. Many people do not realize that homes are always moving - expanding and contracting. Seasonal gaps like what you've are typical of winter, when the lumber in homes tends to shrink from the dry air.
The best thing to do is to remove all the old caulk and then re-caulk the gap using an acrylic latex caulk. Typically, this kind of caulk will last several years. If you want caulk to last longer, you'd need to use silicone but the disadvantage of that is that it can't be painted and, since it isn't water soluble, it is a lot harder to work with.