General usage:
* The company is in arrears on its rent payments.
* He was struggling to pay off his mortgage arrears.
* The library fines were in arrears.
More specific examples:
* The government was facing pressure to address the growing backlog of unemployment benefits in arrears.
* After a long period of financial hardship, the family was finally able to clear their debt arrears.
* The landlord was threatening to evict the tenants for being in arrears on their rent.
Using "in arrears" as an adjective:
* The in-arrears account was flagged for immediate attention.
* The in-arrears payments were a significant burden on the company's finances.
Note: "Arrears" is always plural.