If you have fish in the tank while it is cycling, you need to do as many pwcs as it takes to keep the ammonia and/or nitrITE level down below 0.5ppm. If you can get it closer to 0.25pm that's even better. Any higher than 0.5 and you're risking the health of the fish.
If you were doing a fishless cycle, you can keep the ammonia levels higher than that because there is no livestock. The bacteria will still grow, but it will take a little longer. On average, cycling with fish can take anywhere from 4-6 weeks, give or take.
You can shorten the timeframe by getting some filter media from an established tank and putting it in your filter. Know anyone with a tank?
As Jim suggested, it's probablya good idea to test daily and do a PWC
if those levels go over their benchmarks.