The way the rules are set up makes it easy. The shot clock starts when the ball is legally touched and the 8 second count starts at the same time as well. The 8 second count also doesn't restart if the ball goes out of bounds or there's a timeout. So when the shot clock hits 15, it's a violation.

24 - 8 = ? :confused:

It used to be 16 but that's because of how the shot clock used to count down. I believe it used to show 24 for a full second before it countdown to 23. It did this so when the shot clock had 0 on the clock, it would be a violation. With the shot clock now showing tenths of a second under 5 seconds, they had to change the way the shot clock would show when counting down. Now when the clock starts, it shows 23 immediately. As such, the "magic number" on the shot clock has to be 15 to account for a full 8 seconds.

Or ... stated a different way, previously, the instant the clock first said 15, it was 15.0... but now the instant the clock first says 15, it's 15.9999...

Boom bam, baby
 

That's good stuff right there.

Count slower.
While standing during warm-ups I'll silent count ten and five then glance at the clock to see if I'm off.

When I have little going on in the backcourt and someone walking the ball up court, I'll peek at the clock to gauge myself every now and again.

I do that too; probably once every other game. It's usually when the dribbler is the only BC player.