I didnt give my 2 weeks at my first 2 jobs, both before i was 18. But since then, i have always given my 2 weeks. I think it depends on the job though. My last job that i worked for was a small company, and they really depended on me, and i was a big part of the company. So i could not feel right with myself without giving them my 2 weeks. And it has worked out pretty good, because i have been able to help them out when i have down time with my current job to keep myself busy, and i know i always have a job with them if this one doesnt work out.