I don't like numbers that end in anything except a 0 but 5s are okay as well. If I see a number I try to consolidate it down with this weird and frankly nonsensical thing I have in my brain. Say I see the number 5246 someplace. I'll go "5 x 2 = 10 and 4 + 6 = 10 so this number is okay" because both 'sides' can be reduced to the same number, and the fact both are 10 is a bonus.