I continued smoking for about two weeks after I got my cig-alike kit, while I waited for more cartos to arrive in the mail. If I'd ordered extra cartos in the beginning, I probably would have quit within a few days, if not the next day. You do have to sort of adjust to vaping because the draw is different, and different PG/VG ratios and nicotine levels work differently for everyone and you have to tweak things to figure out what works best for you.
I think the thing that helped me and my husband most was not going into vaping thinking, "I HAVE to like this and quit smoking!" We both started vaping thinking, "If I like this better than cigs, that's great. If not, that's ok, too," and just let the quitting happen naturally. After we found flavors we liked, we didn't even try to quit smoking, it just happened. I think I had one major craving after about a week of vaping, but I vaped some higher nicotine for about five minutes, the craving passed, and I haven't had any bad ones since then.