Basically, it is important to check whether the customer's payment behavior is changing. Longer payment targets are always a reason to take a closer look at the customer. This applies even more if the customer exceeds the payment targets or even runs into dunning stages.
If the customer has had fixed payment terms for his open accounts payable up to now and these terms are now changing, then this is also a reason to follow up.
Particularly relevant are situations in which the customer has previously taken a cash discount and now becomes a gross payer. This suggests, due to the usually with the discount connected large discounting at least on liquidity bottlenecks. Thus, in such a situation special caution is required.
There are however still further aspects:
If, for example, the sales volume generated with the customer is reduced and the payment target is extended at the same time, a review should also be conducted.
Some companies also have the strategy, when payment difficulties are foreseeable, to cover themselves comprehensively with the suppliers beforehand. If unusual order patterns are to be recognized based on the experience with the customer, one should be just as vigilant.
Finally, complaints behavior may also play a role. If the number of complaints increases, in part without justification, this may also be a strategy for delaying payments.