I went in May during peak tulip viewing season, so the city was pretty full. I did not get a timed ticket in advance. I showed up my very first evening in the city at 6:00PM and found absolutely no line whatsoever - walked right up to the ticket window to show my Museumkaart and then stepped directly over to the security checkpoint to open up my purse for the guard. It was a great visit. I had plenty of time to really look at everything and read the descriptions. I did not feel in the least like I was getting pushed along with the crowd (like trying to see some of the more famous Rembrandt or Vermeer paintings at The Rijks).
I was staying in a hotel not far from the Anne Frank House and I did walk past there several other times during the morning and mid day and saw long lines at those times.
You can get through the entire place in about 90 minutes, so if you cannot get a timed ticket I would highly suggest going in the evening and at least doing a walk by to see what the line looks like. Even if you aren't staying at a hotel nearby, it's not a total waste of time if you can't get in - the neighborhood is a nice place to stroll in the evening and there are several good restaurants and brown cafes not far from there if you are looking for a place to eat or drink.