It could take 1 day (for the lucky ones) or many years. Of course it is a two week wait inbetween. But one time I heard that your chances are only about twice a year of a pregnancy occuring. I think all that was calculating if ovulation was missed by a day or other random factors that could occur. For me it took exactly 4 months each time...haha, so I gues my odds are 3 times a year. Alos, Most people try for a year before seeking help, so just to give you a time frame. But just keep on trying!
If you want to help your chances, you can buy those desposible ovulation tests to help determine when it is your best opportunity to concieve. They sell it over the counter next to the pregnancy tests. Also, when you're ready to start checking if you're preggo, you should buy a digital test because no matter how low your HCG levels are it will show up positive compared to the tests with the lines that can take a lot longer to give you that second line to positive outcome. I used clearview easy digital and my HCG levels showed two and 1/2 weeks after I concieved which was before my period was even due.
i highly recommend the book "taking charge of your fertility." i read it months before we started trying and we got pregnant on my 3rd cycle of trying! we feel very blessed!! the book helped educate me quite a bit...it taught me how to chart my temps, etc and get to know my body better. it was really wonderful. but on average, i think it takes a healthy woman 6-12 months. as you get older, it can be harder, but you should be fine. good luck to you!! pregnancy is a true miracle. :-)
side note-we had sex every other day and as soon as i knew i was ovulating (using the ovulation pred kit as another girl had mentioned) we would do it daily. if you don't yet know your cycle or exactly when you are ovulating, it's good that you are having regular sex.