When I started working as a computer programmer, I was proud of my ability to switch from a project to another. I wrongly believed that there wasn't any cost involved, after your brain gets used to it.
During my work at a big telecommunication company in Argentina I experienced a situation which showed me that I was completed wrong. Due to the crisis in the U.S.A. most of the software projects were outsourced as soon as possible to India, Brazil and Argentina. This completely overloaded our department: We were around ca. 21 developers and we had ca. 23 projects. During two months I worked in three projects: one on the morning, other in the afternoon and the last one when I had idle moments on the other ones -on weekends-.
After a couple of weeks I realized that the switching between the projects was taking most of my time. I couldn't remember where I have stopped working on the web services yesterday. When doing bugfixing I repeated the tests because the results I had wrote down didn't showed a pattern. And I started debugging soon after the project switch to have enough time to find out the bug. The communication with the analysts in U.S.A. was too slow because I had to wait half a day to answer.
There was one positive effect of project switching. Our manager realized that the performance of the department was decreasing. The satisfaction of the customer was going down, as the survey showed; and the number of opened tickets in the projects was sky rocketing. The situation was so bad, that she was able to persuade the high management to support the standardization of our development process. We had four hours of internal training -organized by the department- every two weeks and regular meetings were set up to discuss common problems and possible solutions.
However today I would consider project switching a symptom pointing out that our development process is ill. So it is better to try to avoid it than to be proud of your ability to jump from one project to the other one and to write it down on yours application letters.
If you have to opportunity to talk with your manager, here is an excellent article about this topic:
http://www.infoq.com/articles/multitasking-problems
