Depends on the wax. Usually, the directions will tell. However, that being said I ran into complete confusion with a wax. The directions stated a wipe on and wipe off wax (WOWO), however, the website said wipe on and let it haze (5 - 10 minute wait). I just did the WOWO and had no issues.
If there are no instructions or not a WOWO wax: I would do the finger swipe test. If the wax comes off easy with a swipe of your finger than it is ready. This method applies to both liquid and paste waxes.
My guess if you wait about 10 - 15 minutes would be a general guess. I hope this helps.