From a few hours to several years, assuming it is guideline compliant or it will be rejected. Guidelines are listed at DMOZ.
DMOZ is not a listing service, it is staffed by volunteers and seeks to provide categorized sites for the surfer. So editors try and find sites that basically have unique content and add them. Some of those sites will be ones submitted by webmasters for consideration for listing in the category submitted to. But that is by no manner of means our only source.
For instance I edited in a category for the last three weeks that I have not edited for 9 months. I left it pretty much up to date, but who knows when I will go back, depends on the other categories I edit, depends on how much spare time I have over the next, say, year also depends on how I feel. Sorry but DMOZ is a hobby for all editors and whilst some spend hours per day some only spend minutes a month.
Best way to get the Q's down is to join, pass the tests for becoming an editor and then spend a great deal of your spare time editing. It is great fun, addictive and some times we get called lazy, corrupt, a joke, that our work suchs and just sometimes some people say thank you, well I think I can remember one in my 9 years, but we do nopt edit for thanks, no one ever gives it anyway.
