DD's Dad - not a penny for twelve flipping years. Then regular payments of £70 a month ever since with not one missed. He finally grew up, 12 years late...
DS1's Dad - not a penny. CSA originally did a zero award due to the time he spent with DS1, but even though that stopped in August (his choice, long story, to go with Ex's partner hurting DS1), he hasn't paid a penny.
Not going to CSA, he would fight it every step of the way, had 12 years of that with DD's Dad, CBA to do it again, especially as it would only be for £5 a week as he's too lazy to work, AND it would cause all manner of verbal abuse from his partner who I see every day on the school run.
DS2 & DS3's Dad - pays every week, without fail, over and above the CSA levels, never missed a payment, although it's usually one day late once a month as it is due on a Thursday, and he pays on a Friday in the week he gets paid.
So some idiots that refuse to pay for over a decade eventually come round, grow up and start making regular payments, others are just arseholes that will never pay, and some are decent Fathers and would never miss a payment...