I also install alot of gutters. Theyre good, quick, easy, money-makers. To be honest with you. And one of the last pieces I needed to the gutter puzzle, Lefty provided to me (how much roofing can each downspout drain).
I can’t argue with any of you, since you all seem to agree with eachother. But it bothered me a little to be so different, that I called around to my best local guys that are friends of mine, and they all said 16."
Additionally, I looked for specs everywhere online, and I couldn’t find any concrete evidence on the spacing of brackets with englert or berger (large gutter supply manufacturers in my area). As a matter of fact, I couldn’t find anything addressing the amount of brackets, period.
The one thing in my favor, of all the gutters I crushed (and most I paid for, until I learned to put 2x4’s in them), NONE had 16" spacing, and I’ve never tried to do any less than 16". So 16 seems to be standard amongst the best of the best in my area. I haven’t seen differently yet.