We always say that in good credit control, prevention is better than cure - collections and recovery action should be for the bad debts you didn't see coming, not the ones you did.
But how do you know who's going to pay on time, and who's not going to pay at all?
If you've worked in credit control for long enough, it will be instinctive, a kind of sixth sense based on the myriad different factors that contribute towards a company's risk profile.