I have worked for (6) Fortune 100 companies in the IT space in my 20 year career to date and I also stick with the rule that you should never quit a job when you do not have one, and only give two weeks after you already started the new job for at least two weeks.
Take two weeks vacation, sick leave, don’t show up, whatever and start your new job but do not email a resignation until you have signed your health benefits with the new company which was my milestone.
Why?
There is a high likelihood you will get to the new job and immediately realize it was not what was sold at the interview. Yes, yes the first two weeks are training but within that time you should be listening, asking questions, talking to co-workers, reading the benefits on the intranet and confirming that is the job you want to be in. Plus, you get a chance to review the health benefits and make sure it meets your expectations vs. what was in the glossy brochure during the interview. Worst case, if it is not what you expected, you send a letter of immediate resignation to HR, politely walk your laptop to IT, walk to your car and go back to your first job like nothing happened (I have done it). They will write you off as a flake, false hire etc. but retribution is rare as you literally were there for such a short time and HR has other things to do like reopen the requisition. Best case is the job is everything you imagined so far, you remain excited and email your two weeks notice to your old job while replying to all the “why are you quitting????” emails when you get home from your new job.
But, won’t I hurt the first job’s feelings?
Who gives a BEEP, you already know you are not going back and you are in the job you want. Do not feel guilty about not doing Knowledge Transfer etc. since you can reply to emails after work hours and worst case they terminate you immediately after which you can focus 100% on the new job.
I felt compelled to share this as I have witnessed people quitting long term jobs only to take a new role and be crushed about how they are walking into a CLUSTER* or their start date be pushed and uncertainty happen from Day 1.
Remember, companies are not families, they are legal entities designed to make profit.