[Anechoic]

It really doesn't take much longer to go through the process. Show up 3 minutes earlier if you have to.

YMMV with respect to the additional time. I also opt out and have had to wait as long as 15 minutes for the pat down (and to make matters worse in that instance, there was an elderly passenger behind me who had a medical exemption from the scanner and they waved him through while I had to stand and wait).

My advice is that if you do plan to opt out, allow for more than 3 minutes.

[toomuchtodo]

Most opt outs cost you about 15 minutes extra; one time flying from MIA to ORD, I had to wait 40 minutes extra because I opted out.