I keep hearing/ reading about this, and I am still extremely nervous about deviating from the standard 60 minute boil. Can anybody fill me in on the purposes of adjusting boil times?
I think a 90-minute boil is the standard and 60-minute is the deviation, used by brewers who want to save money on utilities. 
I seldom do a 90 min. boil. I wait til the hot break forms, give it maybe 10 min. to clear, and then start my 60 min. timing.
To the OP…there’s really nothing wrong with doing a 90 min. boil if you need/want to. There is so little hop utilization past 60 min. that you’ll never notice the affect on bittering. Sometimes if I’m using all pils malt I’ll do a 90 min. boil to make sure I drive off SMM, but not always. Sometimes if my gravity is short after my normal boil I’ll go a bit longer to boil off more and hit the OG I’m going for.
